An - Najah National University Faculty of Graduated Studies The Effects of Light Intensity on Day and Night Shift Nurses' Health Performance By Noorhan Fareed Al - Sheikh Mohammad Supervisor Prof. Issam Rashid Adbel-Raziq Co-Supervisor Dr. Sharif Mohammad Musameh This Thesis is submitted in Partial Fulfillment of Requirements for the Degree of Master of Physical Sciences Faculty of Graduated Studies, An - Najah National University – Nablus, Palestine 2013 iii Dedication To the angles disguised in human appearance to guide me through my way ….to the candle that burned itself to light my life to my parents, whose encouragement is constantly rushing to nature my souls, to one whose eyes shine with hope and his smiles with love, to the one who shares my life … to my husband Hassan, to my sisters and brothers, to son of my sisters, to my best friend Maram…..to all of my new family with respect and love. iv Acknowledgments I am very grateful to my respectable supervisors Prof. Dr. Issam Rashid Abdel – Raziq and Dr. Sharif Musameh, for their helpful efforts, fruitful guidance and continual encouragement throughout entire research. Special thanks for Dr. Subhi Saleh for his encouragement through my study, to my brother yousef, my husband Hassan, and my friend Maram for their help throughout my research, and to Hospital manager, nurses for their help and cooperation to make this research possible. v االقرار :أنا الموقع أدناه مقدم الرسالة التي تحمل العنوان The Effects of Light Intensity on Day and Night Shift Nurses' Health Performance اقر بأن ما اشتملت عليه هذه الرسالة، أنما هي نتاج جهدي الخاص، باستثناء ما تمت اإلشارة إليه ككل، أو أي جزء منها لم يقدم من قبل لنيل أي درجة علمية أو بحث حيثما ورد، وأن هذه الرسالة .علمي لدى أي مؤسسة تعليمية أو بحثية أخرى Declaration This work provided in this thesis, unless other referenced, is the researcher's own work, and has not been submitted elsewhere for any other degree or qualification. Student's name: اسم الطالب: Signature: التوقيع: Date: التاريخ : vi List of Contents Subject Page Dedication III Acknowledgment IV Declaration V List of Contents VI List of Tables VIII List of Figures XII List of Abbreviations XIV Abstract XV Chapter One: Introduction 1 1.1 Background 1 1.2 Previous Studies 4 1.3 Objectives of this Study 8 Chapter two: Theoretical Background 9 2.1 Absorption of Light 9 2.2 The Effect of Intensity of Light on Humans 10 2.2.1 Blood Oxygen Saturation 10 2.2.2 Blood Pressure 11 2.2.3 Heart Pulse Rate 12 2.2.4 Tympanic Temperature 13 2.3 Sound Pressure Level 14 Chapter Three: Methodology 14 3.1 Study Design 14 3.2 Population Sample 17 3.3 Stage of Study 18 3.4 Timetable of Study 18 3.5 Experimental Apparatus 18 3.6 Statistical Analysis 21 Chapter Four: Measurements and Results 22 4.1 Measuring of Light Intensity and Sound Pressure Level 22 4.2 Measurements of Health Effects of Light Intensity 23 4.2.1 Blood Oxygen Saturation, Pulse Rate, and Arterial Blood Pressure (Systolic and Diastolic) Results 23 4.3 Data Analysis of Result of Light Dependent Health Parameters in the Selected Hospitals 51 4.4 Personal Health Effects Dependence 59 4.4.1 Age Effect 59 4.4.2 Duration of Employment Health Effects 62 vii Dependence Chapter Five: Discussion and Recommendations 65 5.1 Discussion 65 5.2 Recommendations 69 References 70 Appendix A: The measured date for all nurses in four different hospitals 75 Appendix B: Ethics permission and consent form 80 ب الملخص viii List of Table Table Page Table 1.1: Recommended illumination intensities in lux in different work spaces. 3 Table 3.1: The selected sample in four hospitals 17 Table 4.1: Sound pressure level and intensity of light for all hospital before and after starts and finishes their shifts 23 Table 4.2: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in Rafidia governmental hospital at day shift (2 p.m – 9 p.m) 24 Table 4.3: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in Rafidia governmental hospital at night shift (9 p.m – 4 a.m) 25 Table 4.4: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in Nablus Specialized hospital at day shift (2 p.m – 9 p.m) 26 Table 4.5: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in Nablus Specialized hospital at night shift (9 p.m – 4 a.m) 27 Table 4.6: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in specialized Arab Nablus hospital at day shift (2 p.m – 9 p.m) 28 Table 4.7: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in specialized Arab Nablus hospital at night shift (9 p.m – 4 a.m) 29 Table 4.8: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of selected nurses in Union hospital at day shift (2 p.m – 9 p.m) 30 Table 4.9: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied 31 ix variables of selected nurses in Union hospital at night shift (9 p.m – 4 a.m) Table 4.10: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in Rafidia governmental hospital at day shift (2 p.m – 9 p.m) 32 Table 4.11: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in Nablus Specialized hospital at day shift (2 p.m – 9 p.m) 33 Table 4.12: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in specialized Arab Nablus hospital at day shift (2 p.m – 9 p.m) 34 Table 4.13: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in Union hospital at day shift (2 p.m – 9 p.m) 35 Table 4.14: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Rafidia governmental hospital at day shift (2 p.m – 9 p.m) 36 Table 4.15: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Nablus Specialized hospital at day shift (2 p.m – 9 p.m) 37 Table 4.16: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in specialized Arab Nablus hospital at day (2 p.m – 9 p.m) 38 Table 4.17: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Union hospital at shift (2 p.m – 9 p.m) 39 Table 4.18: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in Rafidia governmental hospital at night shift (9 p.m – 4 a.m) 40 Table 4.19: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied 41 x variables of male nurses in Nablus Specialized hospital at night shift (9 p.m – 4 a.m) Table 4.20: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in specialized Arab Nablus hospital at night shift (9 p.m – 4 a.m) 42 Table 4.21: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of male nurses in Union hospital at night shift (9 p.m – 4 a.m) 43 Table 4.22: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Rafidia governmental hospital at night shift (9 p.m – 4 a.m) 44 Table 4.23: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Nablus Specialized hospital at night shift (9 p.m – 4 a.m) 45 Table 4.24: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in specialized Arab Nablus hospital at night shift (9 p.m – 4 a.m) 46 Table 4.25: Minimum (Min), maximum (Max), mean, and standard deviation (S.D) values of studied variables of female nurses in Union hospital at night shift (9 p.m – 4 a.m) 47 Table 4.26: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for all nurses for shift (2 p.m – 9 p.m) 48 Table 4.27: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for all nurses at night shift (9 p.m – 4 a.m) 49 Table 4.28: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for male nurses at day shift (2 p.m – 9 p.m) 49 Table 4.29: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) 50 xi before and after exposure to light intensity for male nurses at night shift (9 p.m – 4 a.m) Table 4.30: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for female nurses at day shift (2 p.m – 9 p.m) 50 Table 4.31: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for male nurses for shift (9 p.m – 4 a.m) 51 Table 4.32: Paired sample correlation of all studied variables before (b) and after (a) exposure to light intensities for all selected nurses in all hospitals for shift (2 p.m – 9 p.m) 52 Table 4.33: Paired sample correlation of all studied variables before (b) and after (a) exposure to light intensities for all selected nurses in all hospitals for shift (9 p.m – 7 a.m) 53 xii List of Figures Figure page Fig. 1.1: The electromagnetic spectrum 1 Fig. 3.1: Lux meter 19 Fig. 3.2: Automatic Blood Pressure Monitor Micro Life AG 19 Fig. 3.3: Pulse Oximeter LM – 800 20 Fig. 3.4: The GT–302 / GT–30 –1 Ear Thermometer 20 Fig. 3.5: Sound Pressure Level Meter Model 2900 Type2 21 Fig. 4.1: Mean values of blood oxygen saturation (SPO2) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m) 54 Fig. 4.2: Mean values of heart pulse rate (HPR) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m). 54 Fig. 4.3: Mean values of systolic blood pressure (SBP) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m). 55 Fig. 4.4: Mean values of diastolic blood pressure (DBP) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m). 55 Fig. 4.5: Mean values of temperature (T) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m). 56 Fig. 4.6: Mean values of blood oxygen saturation (SPO2) of nurses according to intensity of light (Lux) in each hospital shift (9 p.m - 7 a.m). 56 Fig. 4.7: Mean values of heart pulse rate (HPR) of nurses according to intensity of light (Lux) in each hospital shift (9 p.m - 7 a.m). 57 Fig. 4.8: Mean values of systolic blood pressure (SBP) of nurses according to intensity of light (Lux) in each hospital shift (9 p.m - 7 a.m). 57 Fig. 4.9: Mean values of diastolic blood pressure (DBP) of nurses according to intensity of light (Lux) in each hospital shift (9 p.m - 7 a.m). 58 xiii Fig. 4.10: Mean values of temperature (T) of nurses according to intensity of light (Lux) in each hospital shift (2 p.m – 9 p.m). 58 Fig. 4.11: Mean value of blood oxygen saturation (SPO2%) of nurses as a function of mean value of age in each hospital. 59 Fig. 4.12: Mean value of heart pulse rate (HPR) of nurses as a function of mean value of age in each hospital. 60 Fig. 4.13: Mean value of systolic blood pressure (SBP) of nurses as a function of mean value of age in each hospital. 60 Fig. 4.14: Mean value of diastolic blood pressure (DBP) of nurses as a function of mean value of age in each hospital 61 Fig. 4.15: Mean value of temperature of nurses as a function of mean value of age in each hospital. 61 Fig. 4.16: Mean value of blood oxygen saturation (SPO2%) of nurses as a function of mean value of duration of employment in each hospital. 62 Fig. 4.17: Mean value of heart pulse rate (HPR) of nurses as a function of mean value of duration of employment in each hospital. 62 Fig. 4.18: Mean value of systolic blood pressure (SBP) of nurses as a function of mean value of duration of employment in each hospital 63 Fig. 4.19: Mean value of diastolic blood pressure (DBP) of nurses as a function of mean value of duration of employment in each hospital 63 Fig. 4.20: Mean value of temperature (T) of nurses as a function of mean value of duration of employment in each hospital. 65 xiv List of Abbreviations a After a.m Before Morning ANOVA Analysis of Variance b Before dB Decibel DBP Diastolic blood pressure H1 Union Hospital H2 Specialized Arab Nablus Hospital H3 Specialized Nablus Hospital H4 Rafidia Governmental Hospital HPR Heart Pulse Rate I Transmitted Light Io Incident Light LI Light Intensity Log Logarithmic Lux Unit of Illumination Max Maximum Min Minimum NICU Newborn Intensive Care unit Nm Nanometer OSHA The Occupational Safety and Health Administration Pa. Pascal p.m After Noon P – value Probability R Pearson Correlation Coefficient RMS Root Mean Square SBP Systolic Blood Pressure S.D Standard Deviation SPL Sound Pressure Level SPO2% Blood Oxygen Saturation T Transmitted Coefficient T( o C) Tympanic Temperature WHO World Health Organization xv The Effects of Light Intensity on Day and Night Shift Nurses' Health Performance By Noorhan Fareed Al – Shaikh Supervisor Prof. Issam Rashid Abdel – Raziq Co – supervisor Dr. Sharif Mohammad Musameh Abstract This study shed the light on the effect of light intensity on some of the dependent variables, such as blood oxygen saturation (SPO2%), heart pulse rate (P.R), arterial blood pressure (systolic (SBP), diastolic (DBP)), and tympanic temperature (T) of nurses, in their shift work. The sample consists of 207 nurses of both genders (104 female, 103 male), with mean age 29 years, and the mean duration of employment 6 years, were randomly chosen as a sample to fulfill the aim meant. This sample was taken from four hospitals in Nablus city. The values of light intensity in all hospital ranged from 220 Lux to 1000 Lux, at the day shift, and from 500 Lux to 1700 Lux, at the night shift. Number of measurements concerning the blood oxygen saturation, heart pulse rate, arterial blood pressure (systolic and diastolic), and tympanic temperature at different light intensities were taken for the selected sample before and an after exposure to light. Strong positive correlation (Pearson Correlation Coefficient) with light intensity was found for all measured variables. The statistical result for the dependent variables (SPO2%, P.R, SBP, DBP, T) showed that Pearson correlation coefficient (R) between light intensity and the xvi dependent variables are approximately equal to one, and the Probabilities (P) are < 0.05. It was also found that blood oxygen saturation has Pearson's Coefficient R = 0.980 and probability P = 0.020, whereas heart pulse rate has R = 0.966 and probability P = 0.034, while systolic blood pressure has R = 0.985 and P = 0.015. In addition, diastolic blood pressure has R = 0.989 and P = 0.011, and the values for temperature are R = 0.990 and P = 0.010. This study shows that the health effects of light intensity depend on the light intensity itself, more specifically, nurses exposed to light intensity 1700 Lux, have a significant shift of the measured mean values ( blood oxygen saturation, heart pulse rate, arterial blood pressure (systolic and diastolic ), and tympanic temperature), more than nurses exposed to light intensity less than 500 Lux. 1 Chapter One Introduction 1.1 Introduction: Electromagnetic spectrum covers all possible frequencies, from low frequencies (long-wavelength) to gamma radiation at high frequency (short wavelength) Fig. (1.1). These waves can produce different effects on various materials and devices, and therefore different parts of the electromagnetic spectrum have been used for different purposes. The intensity of radiation is a measure of the energy flux, or it can be defined as the total energy per unit area per unit time Fig. (1.1): The Electromagnetic Spectrum. http://en.wikipedia.org/wiki/Gamma_radiation http://en.wikipedia.org/wiki/Wavelength http://en.wikipedia.org/wiki/Measurement http://en.wikipedia.org/wiki/Energy_flux 2 Light can disrupt the body's production of melatonin, which is a hormone produced by pineal gland in brain, melatonin helps in regulating other hormones and maintains the body's circadian rhythm Human body needs light, in limited quantities. The suitable amounts depend on several factors including the type of activity or work performed by human, the gender and the work environment. The Occupational Safety and Health Administration (OSHA) sets the occupational light standards, suitable for human health such as the recommended illumination intensities in lux in different work spaces. As shown in Table (1.1). (3) 3 Table (1.1): Recommended illumination intensities in lux in different work spaces. Activity Illumination Lux Public areas with dark surroundings 20 – 50 Simple orientation for short visits 50 – 100 Working areas where visual tasks are only occasionally performed 100 – 150 Warehouses, Homes, Theaters, Archives 150 Easy Office Work, Classes 250 Normal Office Work, PC Work, Study Library, Groceries, Show Rooms, Laboratories 500 Supermarkets, Mechanical Workshops, Office Landscapes 750 Normal Drawing Work, Detailed Mechanical Workshops, Operation Theatres 1,000 Detailed Drawing Work, Very Detailed Mechanical Works 1500 - 2000 Performance of visual tasks of low contrast and very small size for prolonged periods of time 2000 - 5000 Performance of very prolonged and exacting visual tasks 5000 - 10000 Performance of very special visual tasks of extremely low contrast and small size 10000 - 20000 Health is defined by the World Health Organization (WHO) as a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity. (4) Well-being is defined by Webster’s dictionary as “a good or satisfactory condition of existence; a state characterized by health, happiness and prosperity”. On the basis of these definitions, light is proposed to have deep influence on health. 4 Health performance is represented by blood oxygen saturation, blood pressure, heart pulse rate and tympanic temperature. The normal values of these factors are as follows; (95 - 100%) for blood oxygen saturation, (70) mmHg for diastolic blood pressure and (120) mmHg for systolic blood pressure, (70) beats/min for heart pulse rate and (37 ) for tympanic temperature 1.2. Previous Studies: Some studies support the relationship between lighting and human performance, body temperature, human circadian pacemaker, blood oxygen saturation and hormone melatonin. Hussein (6) in his study showed that shift work, in particular night work can have negative effects on the health, safety, and well-being of workers. His study clearly showed that bright light administration could not reduce anxiety symptoms, somatic symptoms, severe depression and improved social dysfunction significantly during night shift However, bright light exposure significantly decreased the perception stress and burnout syndrome during night permanent shift. These results suggest that bright light might have provoked changes in perception stress and burnout syndrome of nurses working night permanent shift When body is exposed to low intensity light, during night, a hormone called melatonin is produced by pineal gland in the brain. (7) It has been shown that the hormone reduces both blood pressure and body temperature. Therefore, 5 it has been explored as a treatment option for insomnia, hypertension and cancer People are routinely exposed to electrical lighting in the evening hours during work and social activities. A study carried out by Joshua. (8) of Brigham and Women's Hospital shows that exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could have effects on sleep quality and the body's ability to regulate body temperature, blood and glucose level. A study conducted to explore the effect of night shift on Jordanian nurses at critical care units, using a structured questionnaire describes the effect of night shift among nurses working in critical care units. (9) The results showed that female nurses had a significant difference on sufficient sleep, and interpersonal conflicts. (9) In addition, the results indicated that nurses experience health problems and their work performance were affected by the night shift. The study also indicated that night shift affects critical care nurses well-being. (9) In young – Mental Hospital, a research showed that real night shift workers can improve nocturnal alertness and daytime sleep when they are exposed to bright light in their work place. These improvements can be maximized by attenuating morning light on the way home. (10) Another study showed that melatonin levels dropped by 71%, 67%, 44%, 38% and 16% exposing to one hour of light at mid night using different level of light intensities: 3000, 1000, 500, 350 and 200 lux respectively 6 A study was performed in China on the effect of light on the physiological parameters of the premature relationship with premature infants' physiological parameters and the heart pulse rate respiration showed that pulse rate increased and the blood oxygen saturation decreased as the intensity of light went up Badia in his work, (13) showed that exposure to bright light of 5000 lux elevates body temperature and light exerts a strongly, immediately on physiology and behavior in addition to its powerful influence on circadian organization. (13) The evening exposure to bright light increases the mean total sleep time more than an hour, so it may be an effective treatment for early morning a wakening insomnia. (14) Exposure to early morning light can significantly advance the timing of human circadian pacemaker. The resulted response to such light has a non – linear relationship to illuminance and affected plasma melatonin concentrations. (15) People are exposed to electrical lighting during evening hours in their social activities. A study carried out on nurses working in a newborn intensive care unit (NICU) showed that tympanic temperature was consistently increased when nurses were exposed to bright light during their day and night shifts and their sense of well – being was improved. (16) Light affects both men and women. However, the effect is different through the level of the absolute values of melatonin plasma levels, whereas after exposing to bright light, the suppression of plasma melatonin was 40% 7 greater in woman than men. These findings suggest that, there are sex differences in the nocturnal sensitivity of pineal gland to light. (17) Bright light therapy helps in treatment of non – sad depression and circadian rhythm in dement patients when suffering from delusions or agitation. On the other hand, caution should still be used when using bright light therapy in treating demented patients when agitation develops or increases during bright light therapy. (18) People who are more satisfied with their lighting rate are happier, more comfortable and satisfied with their environment and their work. (19) A study conducted by Z. Zamanian in a university hospital, about the effects of bright light on the rhythms in body temperature, plasma melatonin, plasma cortisol and subjective alertness during shift work, indicated that bright light increased cortisol levels and body temperature and improved alertness significantly during night shift. These results demonstrate that photic stimulation in a hospital setting can have a powerful influence on the adjustment of the circadian system. (20) Artificial light at night disrupts the body's biological clock, significantly reduces the production of a melatonin, and suppresses cancerous growth. People doing overnight work over many years have higher risk of developing cancer, such as breast, prostate or colorectal cancer. (21) Bright light can influence human psychophysiology instantaneously by inducing endocrine suppression of melatonin, increase cortisol levels, other physiological changes enhancement of core body temperature, and http://ascidatabase.com/author.php?author=Z.&last=Zamanian 8 psychological changes reduction of sleepiness, increase of alertness. Exposure to bright light at night increases heart rate and enhanced core body temperature. It had no significant effect at all on cortisol. The effect of bright light on the psychological variables was time independence, since nighttime and daytime bright light reduced sleepiness. (22) Light influences the daily rhythm and humans well-being in a physiological, psychological and biological way beside visual photoreceptors, the human eye also contains non visual photoreceptors. Light does not only enable human to see. It also supportes by light perception, the human biological clock system tells the human body when to regulate multiple body functions such as body tempearture, sleep patterns, congnitive performance, mood, well-being and production of hormones melatonin. (23) It's found that light exposure as brief as a few milliseconds could engender changes in alertness and brain wave activity. (24) 1.3. Objective and aims of this Study In Palestine, there is a lack of information in the field of the effects of light intensities on the workers' health performance. In this study light intensity will be measured. The light intensity will be compare to the recommended values. The effect of light intensity on blood oxygen saturation, systolic and diastolic blood pressure, pulse rate and tympanic temperature, will be studied. http://phys.org/tags/light+exposure/ 9 Chapter Two Theoretical Background This chapter consists of three sections including the absorption theory (Sec.2.1) and the effect of light intensity (Sec 2.2) on blood oxygen saturation (Sec 2.2.1), blood pressure (Sec 2.2.2), heart pulse rate (Sec 2.2.3) and tympanic temperature (Sec2.2.4.). Finally, explanation of some basic information about calculation of the sound pressure levels (Sec 2.3). 2.1. Absorption of Light The absorption of light by human body affect the level of melatonin production. The rhythm and activity of the body depends so much on this level of melatonin. The intensity of light absorbed by a sample depends on the chemical density of the sample, its thickness, the cross section of absorption, and on the incident light intensity on the sample. Beer (25) in his work observed that, the amount of light absorbed by the sample is proportional to the concentration of dissolved substance through the following relation: (1) Where Io and I are the intensity of the incident light and the transmitted light, respectively; σ is the cross section of light absorption by a single particle, N is the density (number of particle per unit volume of absorbing particles and L is the sample thickness. Beer–Lambert law states that there 11 is a logarithmic dependence between the transmissions T of light through a substance and the product of the absorption coefficient of the substance µ, namely: LT )ln( (2) The transmission coefficient T is the ratio between the transmitted intensity I and the incident intensity Io. (25) 2.2. The Effect of Intensity of Light on Human Being Several physiological and health effects of intensity of light on humans were observed. This study, will focus on four of them, the change of 1. blood oxygen saturation 2. blood pressure 3. heart pulse rate 4. tympanic temperature 2.2.1. Blood Oxygen Saturation Every living organism requires oxygen for its survival. Health blood oxygen levels are essential for proper functioning of the body. Less amount of oxygen flowing through the blood or oxygen deprivation can lead to organ failure. Lungs are involved in breathing; low oxygen levels suggest lung conditions. Other health conditions can also cause low oxygen levels 11 in blood. Oxygen saturation is defined as the ratio of oxhemoglobin to the total concentration of hemoglobin in blood. A hemoglobin molecule can carry a maximum of four oxygen molecules. For example, if there are 3000 hemoglobin molecules, these can carry as a maximum of 12000 oxygen molecules. If hemoglobin molecules are carrying 11500 oxygen molecules, then the oxygen saturation level will be = 96 %. ( 26) The level can be measured with the help of a pulse oximeter attached to a finger. A 95-100% level is considered as normal or healthy while 80-94% oxygen is considered as low blood oxygen or hypoxemia. In children, 97%oxygen level (at least 97% of the blood stream should be oxygen saturated) is considered as normal. Very low level of oxygen (less than 80%) can lead to serious symptoms. As blood that contains oxygen is circulated to the cell and tissues, a healthy level of oxygen in arteries can keep the organs functioning. Hyperoxia is a condition caused by very high level of oxygen in blood. Breathing high concentration of oxygen can lead to hyperoxia which is an equally serious condition. It causes cell death and serious damage, especially to the central nervous system, eye and lungs. (27) 2.2.2. Blood Pressure Blood pressure is defined as the force of the blood pushing against the walls of the arteries. Each time the heart beats, it pumps blood into the arteries. 12 During each heartbeat, blood varies from a maximum (systolic) and a minimum (diastolic) pressure. (28) Blood pressure is measured by the systolic and diastolic values. The systolic pressure represents the pressure in the arteries as the heart contracts and pumps blood, while the diastolic pressure, represents the pressure in the arteries as the heart relaxes. Normal blood pressure is considered to be 120/70 mm Hg. (29) the value, 120 mmHg is being the systolic pressure while 70 mmHg is being the diastolic pressure. Blood pressure varies during the day. It is lowest when one is sleeping and arises when one is excited, nervous or active. High blood pressure or hypertension means high pressure in arteries. Blood pressure of 140/90 mmHg or above is considered as high blood pressure. In high blood pressure, the heart works harder, and the chances of a stroke or heart attack are greater. (30) 2.2.3. Heart Pulse Rate: Heart Pulse rate is the number of times the heart beats in one minute (beat/min). Pulse rates vary from person to person; pulse rate decreases when somebody is at rest and increases while exercising, because the body needs more oxygen-rich blood. The following is the normal heart pulse rate for different ages: (31) Generally the adults pulse is: 60-100 beats/min. 13 2.2.4. Tympanic Temperature: Body temperature is a common vital sign that is used to determine whether a person is sick or in decent health. Those who believe that they or their children are sick may have to take a measure to an internal body temperature to determine the severity of the illness. One common place to check body temperature is in the ear. This is called the "tympanic temperature" as the formal name for the eardrum is the "tympanic membrane". It only takes several seconds to check tympanic temperature. This method has become so common because it is much faster and accurate than obtaining a rectal or oral temperature. (32) 2.3. Sound Pressure Level Sound pressure level (SPL) or sound level (Lp), measured in decibels, is a logarithmic measure of the energy of particular noise related to a reference noise source of sound pressure Po = 20 µPa which represents the normal threshold of human hearing at 1000 Hz The sound pressure level (LP) is given by the following relation (33) Lp = 20 log (P/P0) Where P (µPa) is the measured root – mean – square (rms) sound pressure. The sound pressure level is measured to normalize the noise effect and to make sure that the only parameter that plays the important role in nurses' activity is light intensity. 14 Chapter Three Methodology 3.1 Study Design Our experimental study which means that we are testing different assumptions by trial and error under conditions constructed and controlled by the researcher. During the experiment, one or more conditions (called independent variables; blood oxygen saturation, heart pulse rate, blood pressure, and tympanic temperature ) are allowed to change in an organized manner and the effects of these changes on associated conditions (called dependent variables; intensity of light) were measured, recorded, validated, and analyzed for arriving at a conclusion. 3.2 Population Sample and Sampling Technique The population sample consists of nurses from four different hospitals in Nablus city. These are Arab Specialist Hospital, Union Hospital, Rafidia Government Hospital, and Specialist Nablus Hospital. This study was applied to 207 nurses, 103 males and 104 females. They were 21 - 50years old. The nurses chosen had no cardiovascular disease, or hearing impairment. The selected nurses had at least a one year work. Moreover the nurses were asked not to smoke or to eat salty food before taking the measurement, to minimize factors which affect blood pressure and other parameters. 15 The best value of the sample is calculated according to Cochran formula (34) : (3) Where, n = best value to select a random sample of nurses in each hospital. Z = 1.96 (p)(q) = estimate of variance, q = 1 - p, p = 0.9, q = 0.1 = acceptable margin of error for proportion being estimated to be 0.055. Using eq. (3) we get: n = 114.3 Applying the correction formula of Cochran: , (4) where, m = correlation sample size that should be used. N = the actual sample number of nurses that found in each hospital . (34) The examined nurses, female or male, have no health problems according to their hospital records. Using eq.(4), the number of nurses that should be examined (m) is:  (71) in Rafidia Government Hospital (H1).  (49) in Specialist Nablus Hospital (H2).  (53) in Specialist Arab Hospital (H3).  (34) in Union Hospital (H4). 16 The measurements were done twice; the first was half an hour before the nurses' start their shift, the second measurement was seven hours after they have done their shift. The nurses were asked to be at rest for half an hour before they started their shift. Light Intensity and Sound Pressure Level were taken every minute during measurement, starting from (2.00 p.m) till (9.00 p.m) and from (9.00 p.m) till (4.00 a.m). The measurements, were taken during a period of one weak for each hospital and on the average 5 times for each nurse. The light intensity was measured in the nurse room at reassigned value of 100 lux before the shift starts. The light intensity was measured in various positions in each hospital and averaged to get the value of light intensity during the shift The values of light intensity in all hospital ranged from 220 Lux to 1000 Lux, at day shift , and from 500 Lux to 1700 Lux, at night shift. Previous studies show that there is a considerable impact of noise on the blood pressure and other parameters. Therefore, nurses working in areas of high noise level were not included in the sample to make sure that the effect of noise on the measured parameters is excluded. The table (3.1) below shows the selected of this sample in these hospitals 17 Table (3.1): The selected sample in four studied hospitals. Male Female Number of nurses Hospital Name H 31 40 71 Rafedia Governmental Hospital H1 24 25 49 Specialized Nablus Hospital H2 30 23 53 Specialized Arab Hospital H3 18 16 34 Union Hospital H4 The sample was taken by convenient sampling technique which means that we talk only the available nurses. 3.3. Stages of Study The stages that have been adopted in this study are as follows: 1. Selecting hospitals in Nablus city 2. Selecting non-smoking nurses and not having health problem. 3. Collecting necessary information concerning the study like; age, employment duration and having other job. 4. Measuring the sound pressure level. 5. Measuring the light intensity of the nurse. 6. The measure parameters are the following: 1. blood oxygen saturation 2. blood pressure 3. heart pulse rate 18 4. tympanic temperature 7. All measurements for each nurse were repeated; twice at day shift (2 p.m – 9 p.m) before the shift starts and after the shift finishes, twice at night shift (9 p.m – 4 a.m) before the shift starts and after the shift finishes. 3.4. Timetable of the Study The measurements were carried out in May and June, 2012. The collected data at hospitals were carried out at day shift (2.00 p.m) before the shift started and in the evening hours at (9.00 p.m) after they finished their shift. In addition the data were carried out at night shift (9.00 p.m) before the shift started and at (4.00 a.m) after the nurses finished their shift work. 3.5. Experimental Apparatus:  Lux Meter, Fig. (3.1) is a special engineering device which is able to measure brightness. Lux Meter especially measures the intensity of light detected by human eye. This light intensity is different from the energy of light reflected by different objects or produced by light sources. Lux meter is widely used to measure the light levels in different areas such as: hospitals, school, laboratories, passageways, and production areas. 19 Fig. (3.1): Lux Meter  Automatic Blood Pressure Monitor micro life AG, Fig. (3.2) Modno. BP 2BHO, Measuring range: (30-280 mmHg) with accuracy ± 2% mm-Hg, and ± 2% for reading heart pulse rate with operating temperature range of +10 °C to +40 °C. This is used for measuring arterial blood pressure (systolic, diastolic and pulse rate). (35) Fig. (3.2): Automatic Blood Pressure Monitor micro l 21  Pulse Oximeter LM-800 Fig. (3.3) with accuracy ± 1%, is used to measure the blood oxygen saturation of each nurse. (36) Fig. (3.3): Pulse Oximeter LM-800  The GT-302/GT-302-1 Ear Thermometer Fig.(3.4) that is used to measure human body temperature through the tympanic temperature of the ear. The display temperature range is 32.0 to 42.9 °C with accuracy range ± 0.01°C. Fig. (3.4): The GT-302/GT-302-1 Ear Thermometer 21  Sound Pressure Level Meter Fig. (3.5), is to measure the noise level in dB. (Quest Technologies U.S.A, Model 2900 type 2) with accuracy of ± 0.5 dB at 25 °C. This device gives the reading with a precision of 0.1dB. (37) Fig. (3.5): Sound pressure level meter model 2900 type 2. 3.6. Statistical Analysis The gathered data were digitalized in a database developed with SPSS and Microsoft excel program. The measurements were analyzed statistically as the following:  Pearson correlation factor (R) and the probability (P) will be used to measure the strength correlation between light intensity levels the dependent variable, and the dependent variables before and after exposure to light. Values with P < 0.05 were considered statistically significant. 22 Chapter Four Measurements and Results This chapter includes the measured data and results which conducted on the sample of nurses in the hospitals in Nablus city. The following physical quantities were measured in the hospitals 1. Light intensity level (LI) 2. Sound pressure level (SPL) 3. Systolic (SBP) and diastolic (DBP) blood pressure 4. Heart pulse rate (HPR) 5. Blood oxygen saturation (SPO2%) 6. Tympanic temperature (T) 4.1 Measuring of light intensity and sound pressure level The other parameters were taken twice in each shift before starting and after finishing each shift. The sample was composed of 207 nurses, 104 females and 103 males. The nurses' ages were between 21 to 50 years and the duration of employment from 1 to 30 year. The results of measurement of light intensity and sound pressure level for all hospital before and after are shown in (Table 4.1). 23 Table (4.1): Sound pressure level and light intensity for all hospital before and after the nurses start and finish their work Average value of LI at night shift (after) (Lux) Average value of LI at day shift (after) (Lux) LI (before) For two shifts (Lux) Average value of SPL (dB(A)) For two shifts H 1700 1000 100 50 H1 900 700 100 50 H2 800 500 100 50 H3 500 220 100 50 H4 Where H1 is Rafidia Government Hospital, H2 Specialist Nablus Hospital, H3 is Arab Specialist Hospital, H4 is Union Hospital. 4.2 Measurements of Health Effects of Light Intensity 1. In this section the health parameters which depend on light intensity as blood oxygen saturation, pulse rate, arterial blood pressure (systolic and diastolic) and tympanic temperature are measured. 4.2.1 Blood Oxygen Saturation, Pulse Rate, and Arterial Blood Pressure (systolic and diastolic), and Tympanic Temperature Results Minimum, maximum, mean, and standard deviation of mean values of duration of employment, age, blood oxygen saturation (SPO2%), pulse rate (P.R), systolic and diastolic pressure (SBP and DBP), tympanic temperature 24 before (b) and after (a) exposure to bright light for all selected nurses in all hospitals at shift (2 p.m – 9 p.m) and (9 p.m – 4 a.m) are presented in Tables 4.2 to 4.9. Table (4.2): Min, Max, mean, and S.D values of studied variables for selected nurses in Rafidia governmental hospital (H1)at day shift (2 p.m – 9 p.m). Rafedia Governmental Hospital (H1) At average LI (1000 Lux) S.D Mean Max Min Variables 8 33 55 22 Age (years) 6 8 25 1 Duration of employment (years) 1 98 100 94 SPO2% (b) 1 95 97 91 SPO2% (a) 12 124 151 90 SBP mmHg (b) 9 136 151 115 SBP mmHg (a) 10 78 95 50 DBP mmHg (b) 8 86 100 70 DBP mmHg (a) 0.3 36.7 37.1 36.1 T ( o C) (b) 0.2 37.1 37.6 36.7 T ( o C) (a) 10 81 110 56 HPR beats /min (b) 9 90 120 68 HPR beats / min (a) 25 Table (4.3): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Rafidia governmental hospital (H1) at night shift (9 p.m – 4 a.m) Rafedia Governmental Hospital (H1) At average LI (1700 Lux) S.D Mean Max Min Variables 9 31 58 21 Age (years) 7 7 25 1 Duration of employment (years) 2 97 100 93 SPO2% (b) 1 94 98 92 SPO2% (a) 13 127 150 90 SBP mmHg (b) 10 139 151 105 SBP mmHg (a) 10 81 93 52 DBP mmHg (b) 9 89 96 63 DBP mmHg (a) 0.4 36.8 37.6 36.0 T ( o C) (b) 0.3 37.4 37.6 36.2 T ( o C) (a) 12 83 112 63 HPR beats /min (b) 13 93 120 67 HPR beats / min (a) 26 Table (4.4): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Specialized Nablus hospital (H2) at day shift (2 p.m – 9 p.m) Specialized Nablus Hospital (H2) At average LI (700Lux) S.D Mean Max Min Variables 9 31 58 21 Age (years) 7 7 25 1 Duration of employment (years) 1 98 99 95 SPO2% (b) 1 96 98 93 SPO2% (a) 12 122 143 90 SBP mmHg (b) 9 132 150 105 SBP mmHg (a) 9 77 90 52 DBP mmHg (b) 8 83 93 63 DBP mmHg (a) 0.4 36.7 37.0 36.0 T ( o C) (b) 0.3 37.1 37.6 36.2 T ( o C) (a) 13 79 112 60 HPR beats /min (b) 13 86 120 63 HPR beats / min (a) 27 Table (4.5): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Specialized Nablus Hospital (H2) at night shift (9 p.m – 4 a.m). Specialized Nablus Hospital (H2) At average LI (900 Lux) S.D Mean Max Min Variables 8 33 55 22 Age (years) 6 8 25 1 Duration of employment (years) 2 97 99 92 SPO2% (b) 1 95 98 90 SPO2% (a) 11 124 151 90 SBP mmHg (b) 9 135 152 112 SBP mmHg (a) 10 79 95 53 DBP mmHg (b) 8 87 99 70 DBP mmHg (a) 0.3 36.8 37.3 36.1 T ( o C) (b) 0.2 37.2 37.9 36.7 T ( o C) (a) 10 82 115 60 HPR beats /min (b) 10 89 120 70 HPR beats / min (a) 28 Table (4.6): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Specialized Nablus Arab Hospital (H3) at day shift (2 p.m – 9 p.m) Specialized Arab Hospital Nablus (H3) At average LI (500Lux) S.D Mean Max Min Variables 6 26 60 20 Age (years) 4 4 25 1 Duration of employment (years) 1 98 100 95 SPO2% (b) 1 96 99 94 SPO2% (a) 13 116 154 90 SBP mmHg (b) 11 124 160 108 SBP mmHg (a) 7 74 94 65 DBP mmHg (b) 8 80 102 70 DBP mmHg (a) 0.4 36.5 37.1 35.3 T ( o C) (b) 0.3 36.9 37.2 36.0 T ( o C) (a) 11 79 110 52 HPR beats /min (b) 11 85 112 66 HPR beats / min (a) 29 Table (4.7): Min, Max, Mean, and S.D. Values of studied variables for selected nurses in specialized Arab Nablus hospital (H3) at night shift (9 p.m – 4 a.m) . Specialized Arab Hospital Nablus (H3) At average LI (800 Lux) S.D Mean Max Min Variables 6 26 60 20 Age (years) 4 4 25 1 SPO2% (b) 1 97 99 95 SPO2% (a) 1 95 97 93 SBP mmHg (b) 13 119 154 90 SBP mmHg (a) 10 127 158 110 DBP mmHg (b) 9 75 102 65 DBP mmHg (a) 9 83 104 72 T ( o C) (b) 0.4 36.7 37.1 35.3 T ( o C) (a) 0.3 37 37.2 35.7 HPR beats /min (b) 12 81 110 52 HPR beats / min (a) 12 88 120 60 HPR beats / min (a) 31 Table (4.8): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Union Hospital (H4) at day shift (2 p.m – 9 p.m) . Union Hospital (H4) At average LI (220 Lux) S.D Mean Max Min Variables 8 31 50 21 Age (years) 6 7 25 1 Duration of employment (years) 1 98 100 95 SPO2% (b) 1 96 98 93 SPO2% (a) 10 116 141 110 SBP mmHg (b) 9 122 145 112 SBP mmHg (a) 8 72 89 55 DBP mmHg (b) 7 78 93 66 DBP mmHg (a) 0.4 36.2 37.1 35.5 T ( o C) (b) 0.3 36.3 37.2 36.0 T ( o C) (a) 12 75 104 59 HPR beats /min (b) 13 80 110 65 HPR beats / min (a) 31 Table (4.9): Min, Max, Mean, and S.D. values of studied variables for selected nurses in Union hospital (H4) at night shift (9 p.m – 4 a.m). Union Hospital (H4) At average LI (500 Lux) S.D Mean Max Min Variables 8 31 50 21 Age (years) 6 7 25 1 Duration of employment (years) 2 97 100 93 SPO2% (b) 1 95 98 91 SPO2% (a) 10 119 145 110 SBP mmHg (b) 9 126 150 112 SBP mmHg (a) 7 75 90 65 DBP mmHg (b) 7 82 95 70 DBP mmHg (a) 0.4 36.5 37.2 35.5 T ( o C) (b) 0.3 36.7 37.3 36.0 T ( o C) (a) 14 77 110 59 HPR beats /min (b) 14 84 112 65 HPR beats / min (a) Tables (4.10 – 4.17) represent the minimum, maximum, mean, and standard deviation of mean values of duration of employment, age, blood oxygen saturation (SPO2%), pulse rate (P.R), systolic and diastolic pressure (SBP and DBP), tympanic temperature before (b) and after (a) exposure to bright 32 light for male nurses in all hospitals at day shift (2 p.m – 9 p.m) and night shift (9 p.m – 4 a.m). Table (4.10): Min, Max, Mean, and S.D. values of studied variables for male nurses in Rafedia Governmental hospital (H1) at day shift (2 p.m – 9 p.m). Rafedia Governmental Hospital (H1) At average LI (1000 Lux) S.D Mean Max Min Variables 7 31 48 22 Age (years) 5 6 20 1 Duration of employment (years) 1 98 99 94 SPO2% (b) 1 95 97 91 SPO2% (a) 13 118 151 100 SBP mmHg (b) 10 130 151 115 SBP mmHg (a) 11 72 94 58 DBP mmHg (b) 8 82 98 70 DBP mmHg (a) 0.3 36.8 37.0 36.1 T ( o C) (b) 0.2 37.4 37.3 36.7 T ( o C) (a) 12 77 110 56 HPR beats /min (b) 11 88 120 68 HPR beats / min (a) 33 Table (4.11): Min, Max, Mean, and S.D. values of studied variables for male nurses in Specialized Nablus hospital (H2) at day shift (2 p.m – 9 p.m). Specialized Nablus Hospital (H2) At average LI (700 Lux) S.D Mean Max Min Variables 8 29 52 21 Age (years) 6 6 25 1 Duration of employment (years) 1 98 99 96 SPO2% (b) 1 96 98 93 SPO2% (a) 10 113 130 90 SBP mmHg (b) 8 123 135 105 SBP mmHg (a) 8 71 90 60 DBP mmHg (b) 8 77 93 63 DBP mmHg (a) 0.4 37 37 36.0 T ( o C) (b) 0.3 36.9 37 36.2 T ( o C) (a) 12 82 112 60 HPR beats /min (b) 13 87 120 63 HPR beats / min (a) 34 Table (4.12): Min, Max, Mean, and S.D. values of studied variables for male nurses in specialized Arab hospital Nablus (H3) at day shift (2 p.m – 9 p.m). Specialized Arab Hospital Nablus (H3) At average LI (500 Lux) S.D Mean Max Min Variables 7 27 60 20 Age (years) 5 4 25 1 Duration of employment (years) 1 98 99 96 SPO2% (b) 1 95 98 94 SPO2% (a) 14 127 154 99 SBP mmHg (b) 13 134 160 109 SBP mmHg (a) 8 79 94 68 DBP mmHg (b) 7 84 99 73 DBP mmHg (a) 0.4 36.4 36.9 35.3 T ( o C ) (b) 0.3 36.7 37.0 36.0 T ( o C) (a) 17 80 110 52 HPR beats /min (b) 12 85 112 66 HPR beats / min (a) 35 Table (4.13): Min, Max, Mean, and S.D. values of studied variables for male nurses in Union hospital (H4) at day shift (2 p.m – 9 p.m). Union Hospital (H4) At average LI (220 lux) S.D Mean Max Min Variables 10 31 50 21 Age (years) 8 7 25 1 Duration of employment (years) 1 98 100 96 SPO2% (b) 1 97 98 93 SPO2% (a) 9 121 141 110 SBP mmHg (b) 10 126 145 112 SBP mmHg (a) 8 74 85 55 DBP mmHg (b) 7 79 90 66 DBP mmHg (a) 0.3 36.7 37.0 36.2 T ( o C) (b) 0.2 36.9 37.2 36.5 T ( o C) (a) 13 80 104 59 HPR beats /min (b) 13 85 110 65 HPR beats / min (a) 36 Table (4.14): Min, Max, Mean, and S.D. values of studied variables for male nurses in Rafidia governmental hospital (H1) at night shift (9 p.m – 4 a.m). Rafedia Governmental Hospital (H1) At average LI (1700 Lux) S.D Mean Max Min Variables 7 31 48 22 Age (years) 5 6 20 1 Duration of employment (years) 1 97 99 92 SPO2% (b) 1 93 96 90 SPO2% (a) 12 121 151 109 SBP mmHg (b) 9 132 152 120 SBP mmHg (a) 10 74 94 58 DBP mmHg (b) 8 84 99 70 DBP mmHg (a) 0.3 36.8 37.2 36.1 T ( o C) (b) 0.3 37.5 37.9 36.7 T ( o C) (a) 13 79 115 60 HPR beats /min (b) 12 90 120 70 HPR beats / min (a) 37 Table (4.15): Min, Max, Mean, and S.D. values of studied variables for male nurses in Specialized Nablus hospital (H2) at night shift (9 p.m – 4 a.m). Specialized Nablus Hospital (H2) At average LI (900 Lux) S.D Mean Max Min Variables 8 29 52 21 Age (years) 6 6 25 1 Duration of employment (years) 1 97 99 94 SPO2% (b) 1 95 98 93 SPO2% (a) 11 117 135 90 SBP mmHg (b) 8 126 140 105 SBP mmHg (a) 9 73 93 60 DBP mmHg (b) 9 79 96 63 DBP mmHg (a) 0.4 36.7 37.2 36.0 T ( o C) (b) 0.4 37.0 37.6 36.2 T ( o C) (a) 11 83 112 63 HPR beats /min (b) 13 89 120 67 HPR beats / min (a) 38 Table (4.16): Min, Max, Mean, and S.D. values of studied variables for male nurses in specialized Arab Nablus hospital (H3) at night shift (9 p.m – 4 a.m). Specialized Arab Hospital Nablus (H3) At average LI (800 Lux) S.D Mean Max Min Variables 7 27 60 20 Age (years) 5 4 25 1 Duration of employment (years) 1 97 99 95 SPO2% (b) 1 95 97 93 SPO2% (a) 14 130 154 99 SBP mmHg (b) 12 136 158 110 SBP mmHg (a) 9 81 96 68 DBP mmHg (b) 8 87 100 74 DBP mmHg (a) 0.4 36.4 37.0 35.3 T ( o C) (b) 0.3 36.8 37.1 35.7 T ( o C) (a) 14 82 110 52 HPR beats /min (b) 14 88 120 60 HPR beats / min (a) 39 Table (4.17): Min, Max, Mean, and S.D. values of studied variables for male nurses in Union hospital (H4) at night shift (9 p.m – 4 a.m) . Union Hospital (H4) At average LI(500 Lux) S.D Mean Max Min Variables 10 31 50 21 Age (years) 8 7 25 1 Duration of employment (years) 2 97 100 93 SPO2% (b) 2 95 97 91 SPO2% (a) 10 123 145 110 SBP mmHg (b) 10 129 150 112 SBP mmHg (a) 7 77 87 65 DBP mmHg (b) 7 82 90 70 DBP mmHg (a) 0.3 36.8 37.2 36.2 T ( o C) (b) 0.2 37.1 37.3 36.5 T ( o C) (a) 14 83 110 59 HPR beats /min (b) 13 88 111 65 HPR beats / min (a) 41 Tables (4.18 – 4.25) represent the same variables for female nurses in all hospitals at day shift (2 p.m – 9 p.m) and night shift (9 p.m – 4 a.m). Table (4.18): Min, Max, Mean, and S.D. values of studied variables for female nurses in Rafidia governmental hospital (H1) at day shift (2 p.m – 9 p.m) . Rafedia Governmental Hospital (H1) At average LI(1000 Lux) S.D Mean Max Min Variables 9 34 55 24 Age (years) 7 9 25 1 Duration of employment (years) 1 98 100 95 SPO2% (b) 1 94 97 93 SPO2% (a) 11 114 140 90 SBP mmHg (b) 8 127 150 115 SBP mmHg (a) 10 73 95 50 DBP mmHg (b) 7 84 100 70 DBP mmHg (a) 0.2 36.8 37.1 36.2 T ( o C) (b) 0.2 37.4 37.6 36.9 T ( o C) (a) 8 74 92 63 HPR beats /min (b) 7 86 99 75 HPR beats / min (a) 41 Table (4.19): Min, Max, Mean, and S.D. values of studied variables for female nurses in Specialized Nablus hospital (H2) at day shift (2 p.m – 9 p.m). Specialized Nablus Hospital (H2) At average LI (700 Lux) S.D Mean Max Min Variables 9 33 58 23 Age (years) 7 9 25 1 Duration of employment (years) 1 97 99 95 SPO2% (b) 1 94 97 93 SPO2% (a) 13 119 143 90 SBP mmHg (b) 10 130 150 110 SBP mmHg (a) 9 76 89 52 DBP mmHg (b) 8 82 92 65 DBP mmHg (a) 0.3 36.7 37.0 36.1 T ( o C) (b) 0.3 37.0 37.6 36.5 T ( o C) (a) 15 81 112 60 HPR beats /min (b) 14 88 103 69 HPR beats / min (a) 42 Table (4.20): Min, Max, Mean, and S.D. values of studied variables for female nurses in specialized Arab Nablus hospital (H3) at day shift (2 p.m – 9 p.m) . Specialized Arab Hospital Nablus (H3) At average LI (500 Lux) S.D Mean Max Min Variables 3 24 33 20 Age (years) 3 4 12 1 Duration of employment (years) 1 98 100 95 SPO2% (b) 1 95 99 94 SPO2% (a) 10 120 130 90 SBP mmHg (b) 7 127 136 108 SBP mmHg (a) 6 77 89 65 DBP mmHg (b) 9 83 102 70 DBP mmHg (a) 0.3 37 37.1 35.9 T ( o C) (b) 0.3 37.3 37.2 36.0 T ( o C) (a) 7 77 89 63 HPR beats /min (b) 8 83 98 68 HPR beats / min (a) 43 Table (4.21): Min, Max, Mean, and S.D. values of studied variables for female nurses in Union hospital (H4) at day shift (2 p.m – 9 p.m). Union Hospital (H4) At average LI (220 Lux) S.D Mean Max Min Variables 7 31 45 22 Age (years) 4 6 15 1 Duration of employment (years) 1 97 99 95 SPO2% (b) 2 96 98 93 SPO2% (a) 10 124 140 110 SBP mmHg (b) 8 131 145 120 SBP mmHg (a) 7 80 89 68 DBP mmHg (b) 7 86 93 70 DBP mmHg (a) 0.5 36.6 37.1 35.5 T ( o C) (b) 0.3 36.6 37.2 36.0 T ( o C) (a) 11 78 94 64 HPR beats /min (b) 13 84 101 70 HPR beats / min (a) 44 Table (4.22): Min, Max, Mean, and S.D. values of studied variables for female nurses in Rafidia governmental hospital (H1) at night shift (9 p.m – 4 a.m). Rafedia Governmental Hospital (H1) At average LI (1700 Lux) S.D Mean Max Min Variables 9 34 55 24 Age (years) 7 9 25 1 Duration of employment (years) 2 97 99 93 SPO2% (b) 1 93 98 91 SPO2% (a) 10 118 143 90 SBP mmHg (b) 9 131 151 112 SBP mmHg (a) 10 75 95 53 DBP mmHg (b) 7 87 99 74 DBP mmHg (a) 0.2 36.9 37.3 36.4 T ( o C) (b) 0.2 37.6 37.6 37.0 T ( o C) (a) 8 76 92 63 HPR beats /min (b) 8 88 102 75 HPR beats / min (a) 45 Table (4.23): Min, Max, Mean, and S.D. values of studied variables for female nurses in Specialized Nablus hospital (H2) at night shift (9 p.m – 4 a.m). Specialized Nablus Hospital (H2) At average LI (900 Lux ) S.D Mean Max Min Variables 9 33 58 23 Age (years) 7 9 25 1 Duration of employment (years) 2 97 100 93 SPO2% (b) 1 95 96 92 SPO2% (a) 14 121 150 90 SBP mmHg (b) 10 129 151 110 SBP mmHg (a) 10 77 90 52 DBP mmHg (b) 8 81 93 65 DBP mmHg (a) 0.4 36.8 37.6 36.1 T ( o C) (b) 0.3 37.1 37.6 36.5 T ( o C) (a) 14 83 103 63 HPR beats /min (b) 13 88 104 70 HPR beats / min (a) 46 Table (4.24): Min, Max, Mean, and S.D. values of studied variables for female nurses in specialized Arab Nablus hospital (H3) at night shift (9 p.m – 4 a.m). Specialized Arab Hospital Nablus (H3) At average LI (800 Lux) S.D Mean Max Mini Variables 3 24 33 20 Age (years) 3 4 12 1 Duration of employment (years) 1 97 99 95 SPO2% (b) 1 95 97 93 SPO2% (a) 11 123 135 90 SBP mmHg (b) 6 130 138 115 SBP mmHg (a) 10 81 102 65 DBP mmHg (b) 9 85 104 72 DBP mmHg (a) 0.4 36.6 37.1 35.9 T ( o C) (b) 0.3 36.8 37.2 36.2 T ( o C) (a) 8 80 98 63 HPR beats /min (b) 9 87 100 70 HPR beats / min (a) 47 Table (4.25): Min, Max, Mean, and S.D. values of studied variables for female nurses in Union hospital (H4) at night shift (9 p.m – 4 a.m). Union Hospital (H4) At average LI (500 Lux) S.D Mean Max Min Variables 7 31 45 22 Age (years) 4 6 15 1 Duration of employment (years) 1 97 99 94 SPO2% (b) 2 95 98 93 SPO2% (a) 9 126 140 110 SBP mmHg (b) 7 132 145 124 SBP mmHg (a) 7 81 90 70 DBP mmHg (b) 6 86 95 75 DBP mmHg (a) 0.5 36.7 37.2 35.5 T ( o C) (b) 0.4 36.9 37.3 36.0 T ( o C) (a) 13 82 101 64 HPR beats /min (b) 15 88 112 70 HPR beats / min (a) 48 Finally, The net change of blood oxygen saturation, pulse rate, systolic and diastolic pressure, and tympanic temperature before and after exposure to bright light for all nurses, male, and female, at shift day (2 p.m – 9 p.m) and for night shift (9 p.m – 4 a.m) are calculated and shown in (Tables 4.26 - 4.31). Table (4.26): Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for all nurses at day shift (2 p.m – 9 p.m). H4 H3 H2 H1 Differences between means 1.64 2.21 2.30 2.95 SPO2% 6.02 7.62 9.49 11.6 S.B.P mmHg 5.96 6.10 6.64 7.92 D.B.P mmHg 0.10 0.33 0.40 0.43 T( 0 C) 5.16 6.00 6.63 9.16 H.P.R beats/min 49 Table (4.27): Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for all nurses at night shift (9 p.m – 4 a.m). H4 H3 H2 H1 Differences between means 1.81 2.30 2.42 3.00 SPO2% 7.32 8.11 10.7 12.1 S.B.P mmHg 6.85 7.60 7.77 8.01 D.B.P mmHg 0.21 0.36 0.42 0.50 T( 0 C) 6.85 7.00 7.88 9.90 H.P.R beats/min Table (4.28): Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for male nurses at day shift (2 p.m – 9 p.m). H4 H3 H2 H1 Differences between means 1.44 2.20 2.40 3.32 SPO2% 5.00 6.50 9.12 11.4 S.B.P mmHg 5.00 5.17 5.50 10.4 D.B.P mmHg 0.23 0.28 0.30 0.62 T( 0 C) 5.16 5.23 5.56 11.5 H.P.R beats/min 51 Table (4.29): Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for male nurses at night shift (9 p.m – 4 a.m) . H4 H3 H2 H1 Differences between means 2.12 2.45 2.50 3.47 SPO2% 6.12 6.70 9.29 11.4 S.B.P mmHg 5.55 5.94 5.88 10.4 D.B.P mmHg 0.29 0.32 0.37 0.69 T( 0 C) 5.62 6.10 5.54 11.6 H.P.R beats/min Table (4.30): Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for female nurses at day shift (2 p.m – 9 p.m). H4 H3 H2 H1 Differences between means 1.75 2.91 3.02 4.17 SPO2% 6.75 6.48 10.9 12.3 S.B.P mmHg 5.93 5.70 5.94 11.8 D.B.P mmHg 0.28 0.29 0.31 0.66 T( 0 C) 6.00 6.13 6.68 11.6 H.P.R beats/min 51 Table 4.31: Net change of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) before and after exposure to light intensity for female nurses at night shift (9 p.m – 4 a.m). H4 H3 H2 H1 Differences between means 1.88 3.00 3.16 4.28 SPO2% 6.82 7.13 10.6 13.3 S.B.P mmHg 6.06 6.48 6.24 11.8 D.B.P mmHg 0.29 0.30 0.35 0.70 T( 0 C) 6.25 6.38 6.75 11.6 H.P.R beats/min 4.3 Data Analysis of Result of Light Intensity Dependent Health Parameters in the Selected Hospitals Results of light intensity, blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic pressure), and tympanic temperature showed that there is shifting of these measurements after exposure to different intensities of light. It is found that there is a strong positive correlation (Pearson correlation coefficient) between light intensity, as independent variable and blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic pressure), and tympanic temperature at different intensities of light as dependent variables. All of these relationships are presented in Table 4.34 for day shift (2 p.m – 9 p.m), and in Table 4.35 for night shift (9 p.m – 4 a.m). 52 Table 4.32: Paired sample correlation of all studied variables before (b) and after (a) exposure to light intensities for all selected nurses in all hospitals at day shift (2 p.m – 9 p.m). Sig-P- value Correlation Pearson paired variables 0.043 0.957 LI (Lux) and SPO2 % (b) 0.020 0.980 LI (Lux) and SPO2 % (a) 0.011 0.989 LI (Lux) and SBP mmHg (a) 0.073 0.927 LI (Lux) and SBP mmHg (b) 0.019 0.981 LI (Lux) and DBP mmHg (b) 0.015 0.985 LI (Lux) and DBP mmHg (a) 0.404 0.569 LI (Lux) and T (o C) (b) 0.010 0.990 LI (Lux) and T (o C) (a) 0.034 0.966 LI (Lux) and HPR beats/min (b) 0.012 0.988 LI (Lux) and HPR beats/min (a) 53 Table 4.33: Paired sample correlation of all studied variables before (b) and after (a) exposure to light intensities for all selected nurses in all hospitals at night shift (9 p.m – 4 a.m). Sig-P- value Correlation Pearson paired variables 0.084 0.915 LI (Lux) and SPO2 % (b) 0.105 0.895 LI (Lux) and SPO2 % (a) 0.099 0.901 LI (Lux) and SBP mmHg (a) 0.152 0.848 LI (Lux) and SBP mmHg (b) 0.085 0.915 LI (Lux) and DBP mmHg (b) 0.381 0.619 LI (Lux) and DBP mmHg (a) 0.159 0.841 LI (Lux) and T (o C) (b) 0.114 0.886 LI (Lux) and T (o C) (a) 0.246 0.754 LI (Lux) and HPR beats/min (b) 0.185 0.815 LI (Lux) and HPR beats/min (a) Figs (4.1 – 4.5) display relationships between mean values of blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic pressure), and tympanic temperature, and intensity of light in each hospital in day shift (2 p.m – 9 p.m) before (b) and after (a) exposure to light intensity. Where H1 is Rafidia Governmental Hospital, H2 is specialized Nablus hospital, H3 is specialized Arab Nablus Hospital, H4 is Union Hospital. 54 Fig. (4.1): Mean values of blood oxygen saturation (SPO2%) of nurses as a function of light intensity in day shift before (b) and after (a) exposure to light intensity. Fig. (4.2): Mean values of heart pulse rate (HPR) of nurses as a function of light intensity in day shift before (b) and after (a) exposure to light intensity. 55 Fig. (4.3): Mean values of systolic blood pressure (SBP) of nurses as a function of light intensity in day shift before (b) and after (a) exposure to light intensity. Fig. (4.4): Mean values of diastolic blood pressure (SBP) of nurses as a function of light intensity in day shift before (b) and after (a) exposure to light intensity. 56 Fig. (4.5): Mean values of temperature (T) of nurses as a function of light intensity in day shift before (b) and after (a) exposure to light intensity. Figs (4.6 – 4.10) display relationships between mean values of blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic pressure), and tympanic temperature, and intensity of light in night shift before (b) and after (a) exposure to light intensity. Fig. (4.6): Mean values of blood oxygen saturation (SPO2 %) of nurses as a function of light intensity in night shift before (b) and after (a) exposure to light intensity. 57 Fig. (4.7): Mean values of heart pulse rate (HPR) of nurses as a function of light intensity in night shift before (b) and after (a) exposure to light intensity. Fig. (4.8): Mean values of systaltic blood pressure (SBP) of nurses according to intensity of light in night shift before (b) and after (a) exposure to light intensity. 58 Fig. (4.9): Mean values of diastolic blood pressure (DBP) of nurses as a function of light intensity in night shift before (b) and after (a) exposure to light intensity. Fig. (4.10): Mean values of temperature (T) of nurses as a function of light intensity in night shift before (b) and after (a) exposure to light intensity. 59 4.4 Personal Health Effects Dependence In this section there are some personal health effects such as age (Sec 4.4.1), duration of employments (Sec 4.4.2) are discussed. 4.4.1 Age Effect The dependence of the mean value of blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic) on the age of the nurses in the studied hospitals before(b) and after (a) exposure to light intensity are represented in (Figs 4.11 – 4.15). Fig. 4.11: Mean value of blood oxygen saturation (SPO2%) of nurses as a function of mean value of age in each hospital before (b) and after (a) exposure to light intensity. 61 Fig. 4.12: Mean value of heart pulse rate (HPR) of nurses as a function of mean value of age in each hospital before (b) and after (a) exposure to light intensity Figure 4.13: Mean value of systolic blood pressure (SBP) of nurses as a function of mean value of age in each hospital before (b) and after (a) exposure to light intensity. 61 Figure 4.14: Mean value of diastolic blood pressure (DBP) of nurses as a function of mean value of age in each hospital before (b) and after (a) exposure to light intensity. Figure 4.15: Mean value of temperature of nurses as a function of Mean value of age in each hospital before (b) and after (a) exposure to light intensity. It can be observed that there is significant correlation between mean value of blood oxygen saturation, pulse rate, blood pressure (systolic and diastolic) and the age of the selected nurses in the studied hospital . 62 4.4.2 Duration of Employment Health Effects Dependence The dependence of the mean value of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) on the duration of employment of the selected nurses in the studied hospital before (b) and after (a) exposure to light intensity are represented in (Figs 4.16 – 4.20). Fig. 4.16: Mean value of blood oxygen saturation (SPO2%) of nurses as a function of Mean value of duration of employment in each hospital before (b) and after (a) exposure to light intensity. Fig. 4.17: Mean value of heart pulse rate (HPR) of nurses as a function of Mean value of duration of employment in each hospital before (b) and after (a) exposure to light intensity. 63 Fig. 4.18: Mean value of systolic blood pressure (SBP) of nurses as a function of Mean value of duration of employment in each hospital before (b) and after (a) exposure to light intensity. Fig. 4.19: Mean value of diastolic blood pressure (DBP) of nurses as a function of Mean value of duration of employment in each hospital before (b) and after (a) exposure to light intensity. 64 Fig. 4.20: Mean value of temperature of nurses as a function of Mean value of duration of employment in each hospital before (b) and after (a) exposure to light intensity. It can be observed that there is significant correlation between mean value of blood oxygen saturation, pulse rate, and blood pressure (systolic and diastolic) and the duration of employment of the selected nurses in the studied hospital 65 Chapter Five Discussion and Recommendation 5.1 Discussion Light exposure study was carried out on four different hospitals in Nablus city. Light intensity in all studied hospitals ranged from 220 Lux to 1000 Lux at day shift and from 500 Lux to 1700 Lux at night shift. The highest light intensity level (Table 4.1) was observed at Rafidia Governmental Hospital with (1000 Lux at day shift and 1700 Lux at night shift).The lowest at Union Hospital with (220 Lux at day shift and 500 Lux at night shift). Effects of the light intensity on all parameters in night shift were more than in day shift, such as in Rafidia Governmental Hospital the change before and after exposure to light intensity in SPO2% is 2.95% at day shift and 3.00% at night shift, and the change in tympanic temperature is 0.43 0 C at day shift and 0.50 0 C at night shift. The results of measurements of blood pressure (systolic and diastolic blood pressure) show that there are an increase in values with an increase of light intensity in day and night shifts as shown in Figs. 4.4, 4.5, 4.9, and 4.10. That was the case in all hospitals, for all nurses and employment periods. The increment in blood pressure was less for young nurses than for older nurses (Figs.4.14 and 4.15). The newly employed nurses were more 66 affected by light intensity than their mates of higher employment periods,(Figs.4.19 and 4.20). The strength of the results are good as can be understood from the Pearson correlation coefficient and Probability values between light intensity and blood pressure before and after exposure to light are 0.989, 0.985 at day shift, and 0.901, 0.915 at night shift. 0.011 and 0.015 at day shift ,and 0.015, 0.019 at night shift respectively (Tables 4.34 and 4.35). However the results of this study are in agreement with other studies which support that exposure to light intensity leads to increase blood pressure Pandi et al., 2006. The behavior of heart pulse rate as a dependent variable showed a continuous increase with the increase of light intensity (Fig. 4.3) at day shift, and (Fig. 4.8) at night shift. This is in good agreement with the study conducted by Peng et al., 2001 There is a decrease in blood oxygen saturation with the increase of light intensity. That was the case in all hospitals, for all nurses and employment periods. It was clear that the increment in blood oxygen saturation is more for older nurses than for younger nurses and also those newly employed nurses were less affected by light intensity than their mates of higher employment periods. This is in complete agreement with the study conducted by Peng et al., 2001 The measurements for temperature showed that there is an increase in temperature with an increase of light intensity. That was the case in all hospitals, for all nurses and employment periods. The increment in 67 temperature is more for older nurses than for younger nurses. Those newly employed nurses are less affected by light intensity than their mates of higher employment periods. This agrees with the study conducted by Z. Zamanian 2010. The statistical results of the dependent variables (H.P.R, SPO2%, and T) showed that Pearson correlation coefficient between light intensity, (the dependent variable) is approximately equal to one, and the Probability is < 0.05. This indicates that there is a strong correlation (before and after exposure to light intensity) between light intensity and the dependent variables (Tables 4.34 and 4.35) It is apparently noted that all factors (blood oxygen saturation, heart pulse rate, and blood pressure (systolic and diastolic), tympanic temperature) have increased during the night shift since the intensity of light is more than that during day shift. This study showed that the effects of light intensity on human health depends on the light intensity itself. For example, the accepted illumination was in Union hospital (220 lux at day shift and 500 lux at night shift), while the bad effect on health performance for all nurses was less in Rafidia Governmental hospital (1000 lux at day shift and 1700 lux at night shift). The net change in dependent variables before and after exposure to light intensity (Tables 4.28- 4.33) showed that the shift in blood oxygen saturation was 1.64% for LI 220 Lux and 2.95% for LI 1000 Lux, while the shift in heart pulse rate was 5.16 beats /min for LI 220 Lux and 9.16 68 beats/min for LI 1000 Lux. In the case of blood pressure, it was observed that the difference in SBP for LI 220 Lux and 1000 Lux were 6.02 mmHg and 11.62 mmHg, respectively. On the other hand, the difference in DBP for LI 220 Lux and 1000 Lux were 5.96 mmHg and 7.92 mmHg, respectively. Finally, the difference for T were 0.1 o C for LI 220 Lux and 0.43 o C for LI 1000 Lux. The results of this study agree with the result of the other studies that say that SBP and DBP increase as light intensity increasing during night shift workers (Pandi et al 2006). It was found that nurses with seven hours exposure to 1700 Lux had higher blood pressure than the nurses who exposed to 500 Lux. (9) It is observed that the net change in blood oxygen saturation was 3.32% for male and 4.17% for female, while the net change in pulse rate for males and females was 11.54 beats/min and 11.59 beats/min respectively. The shift in SBP was 11.35 mmHg for male and 12.33 mmHg for female. In case of DBP, the net change is 10.38 mmHg for male and 11.75 mmHg for female (Tables 4.29 - 4.30). The results indicate that the females are more affected by light than males. Our results show contradiction to the results of Monteleone P., 1997. As a conclusion, when human expose to light intensity the body absorbs light according to Beer's law. 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Instruction Manual for Models 2900 Integrating and Logging Sound Pressure Level Meter, Quest Technology (1998 b). 75 Bi Consent Form نموذج موافقة على االشتراك في الدراسة أنا الطالبة نورهان فريد يوسف الشيخ محمد ءقسم الفيزيا–كلية الدراسات العليا –جامعة النجاح الوطنية أقوم بدراسة وذلك استكماال لمتطلبات درجة الماجستير بعنوان "تأثير شدة الضوء على صحة الممرضين في فترات عملهم بالليل والنهار" اود االشارة هنا بان اشتراككم في الدراسة لن يتطلب منكم ذكر االسم او ذكر أي معلومات حساسة .اك في هذه الدراسة في أي وقت تشاؤونويحق لكم عدم االشتراك او التوقف عن االشتر .أي معلومات سنأخذها منكم ستكون لغرض البحث العلمي فقط :االسم .نورهان فريد يوسف الشيخ ابراهيم :التوقيع .نورهان فريد جامعة النجاح الوطنية كلية الدراسات العليا عملهم في الليل والنهار اتفي فتر صحة الممرضينعلى الضوءتأثير شدة إعداد نورهان فريد يوسف الشيخ محمد إشراف عصام راشد عبد الرازق. د. أ مسامحمحمد شريف . د قدمت هذه األطروحة استكماال لمتطلبات درجة الماجستير في الفيزياء بكلية الدراسات العليا في فلسطين –جامعة النجاح الوطنية في نابلس 2013 ب دة الضوء على صحة الممرضين في فترات عملهم في الليل والنهارتأثير ش إعداد نورهان فريد يوسف الشيخ محمد إشراف عصام راشد عبد الرازق. د.أ مسامح محمد شريف. د الملخص ألقت هذه الدراسة الضوء على تأثير شدة االضاءة على عدد من العوامل الصحية مثل تركيز ودرجة حرارة الجسم ( االنقباضي واالنبساطي)لب و ضغط الدم األكسجين في الدم ونبض الق كعينة عشوائية من أجل تحقيق ( ذكر 401أنثى و 401) ينممرض 702تم اختيار . الداخلية .الهدف المنشود في مدينة نابلس ( حكومية وخصوصية) أخذ هذه العينة من الممرضين من أربعة مستشفيات لقد تم (4200–000)لوكس في فترة العمل الصباحي و( 4000 –770)حيث بلغت شدة االضاءة .س في فترة العمل الليليكلو وقد تم اخذ عدد من القياسات ذات العالقة بتركيز االكسجين في الدم ونبض القلب وضغط الدم ساعات 2ودرجة حرارة الجسم الداخلي قبل التعرض لشدة االضاءة وبعد ( االنبساطي واالنقباضي) وقد وجد أن هناك عالقة قوية بين شدة االضاءة وكل من تركيز الدم . ض لشدة االضاءةمن التعر حيث كان معامل . ودرجة حرارة الجسم الداخلي( االنقباضي واالنبساطي)ونبض القلب وضغط الدم 0.00> واالحتمالية 4بين المتغيرات وشدة االضاءة تقريبا ارتباط بيرسون على شدة االضاءة بحد تأثير شدة االضاءة على الجوانب الصحية تعتمد اظهرت هذه الدراسة ان ودرجة حرارة ( االنقباضي واالنبساطي) قيم تركيز الدم ونبض القلب وضغط الدم تفقد تغير , ذاتها لوكس من 4200شدة اضاءة الجسم الداخلي بشكل اكبر عند الممرضين الذين تعرضوا ل . لوكس 770الذين تعرضوا ل الممرضين ج في فترة العمل الصباحي كان معامل ارتباط بيرسون بين شدة االضاءة وتركيز االكسجين حيث ان , (0.900)معامل ارتباط بيرسون لنبض القلب بينما كان (. 0.070)واالحتمالية , (0.9.0)بالدم ارتباط معاملوجد أن ( االنقباضي واالنبساطي)وبالنسبة لضغط الدم (. 0.011)واالحتمالية باإلضافة كان معامل ارتباط بيرسون لضغط الدم , ( 0.040)واالحتمالية ( 0.9.0)بيرسون كان ط بيرسون اوبالنسبة لدرجة الحرارة كان معامل ارتب, (0.044)واالحتمالية ( 0.9.9)االنبساطي (.0.040) والحتمالية( 0.990) مسائي ولكن التأثير في الفترة المسائية كان وهذا يعني ان هناك تأثير في فترة العمل الصباحي وال .وذلك بسب ان شدة االضاءة كانت اكبر أعلى