RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,
KARNATAKA, BANGALORE
PROFORMA FOR REGISTRATION OF SUBJECT FOR DISSERTATION
1. NAME OF THE CANDIDATE AND ADDRESS / DR. KIRTHANA KUNIKULLAYA.U#44, 1ST Main, Coconut Garden, Nagarbhavi main road, Banglore-560072
2. NAME OF THE INSTITUTION / M.S. RAMAIAH MEDICAL COLLEGE, BANGALORE-560054
3. COURSE OF STUDY & SUBJECT / M.D. in Physiology
4. DATE OF ADMISSION / 31st MAY 2007
5. TITLE OF THE TOPIC / A COMPARITIVE STUDY OF CIRCADIAN HEART RATE VARIABILITY BETWEEN NIGHT SHIFT AND DAY SHIFT WORKERS
6. BRIEF RESUME OF THE INTENDED WORK:
6.1 INTRODUCTION & NEED FOR THE STUDY:
Sleep is critical to health and a sense of well-being. Working at night goes against the body’s circadian rhythm. Sleep deprivation is very common in today’s society at large. In many occupational settings, such as shift work, BPO employees (Business Process Outsourcing in Telephonic or voice support) who work during non – traditional hours suffer from sleep problems due to disruptions in their normal sleep cycle. Recent studies indicate that sleep deprivation may affect the autonomic nervous system, contributing to high vascular risk. Heart rate variability is one of the most promising markers of autonomic activity. Not much has been documented about Heart rate variability in sleep-deprived individuals, especially in India. Even though an association between sleep deprivation and heart rate variability has been reported by several studies, the sample size has been small and the obtained results are not consistent. It is hypothesized that, there is an increase in the heart rate and a decrease in Heart rate variability in night shift workers (BPO Employees). The purpose of this study is to test the above hypothesis and to assess for any cardiovascular adaptation due to chronic night shift work.
6.2 REVIEW OF LITERATURE:
Shift work results in misalignment between the circadian timing and the sleep – wake schedule, leading to irregular and poor quality sleep1. Shift work is associated with numerous negative effects, including fatigue, decreased alertness, cognitive deficits, increased injuries, and cardiac, gastrointestinal and reproductive disorders2. Previous studies indicate that the circadian timing system of an average night shift worker fails to adapt successfully to such work schedules. In normal populations, autonomic activity shows a circadian pattern, with sympathetic activity prevalent during the day and parasympathetic in the night3. Heart rate and its variability are under sympatho – vagal influence, and reduced heart rate variability and increased heart rate are thought to be a result of autonomic imbalance4. Insomnia is associated with increased heart rate, increased low frequency spectral power, an indicator of increased sympathetic system activity and decreased high frequency power and heart rate variability. These data imply that chronic insomniacs could be at increased risk of development of disorders such as coronary artery disease5. Sleep deprivation results in increased resting blood pressure and no change in heart rate6. Total sleep deprivation appeared to have no substantial effect on cardiac response to spontaneous arousals and awakenings from sleep in healthy subjects7. The fact that Heart rate variability decreases after sleep deprivation was not found to be statistically significant (p=0.26)8. Adaptation rarely occurs despite many years of night shift work, in part because of resumption of full daytime activities and night time sleep during weekends and vacations9. Acute sleep deprivation was associated with increased sympathetic, cardiac and blood pressure modulation, and decreased parasympathetic cardiac modulation. These adverse effects were seen as early as 12 hours of sleep deprivation. There was significant decline in heart rate at 12 and 36 hours of sleep deprivation, as compared with baseline10.
6.3 OBJECTIVES OF THE STUDY:
1. To Evaluate the Heart Rate Variability in Night shift BPO employees and Compare it with Age and sex Matched Day shift workers.
2. To assess for Physiological Adaptation if any in Heart Rate Variability among Chronic Sleep Deprived night shift workers.
7. MATERIALS AND METHODS:
7.1 SOURCE OF THE DATA:
In this study, 30 BPO employees who have Shift Work Schedule will be the subjects and 30 normal controls (normal sleepers). The employees working on Telephonic or voice support will be recruited as Subjects. The study will be undertaken between January 2008 and January 2009. All the BPO companies employing individuals working in shifts would be included for the study. The employees of both sexes consenting to participate in the study would be recruited and similar number of age and sex matched controls (Day shift employees) would be taken for comparison.
Sampling: Purposive non-random
7.2 METHODOLOGY:
Informed consent shall be taken from the volunteers for performing a single channel Electrocardiogram (ECG) in order to determine the heart rate variability. The procedure will be explained to each volunteer before the test. Heart rate variability will be calculated by using RMS Vagus HRV software (RMS, India. History of general health and menstrual history will be taken by a standard questionnaire. A sleep questionnaire will also be administered to all the participants. Volunteers will be screened for general physical health. The measured Heart rate variability will be compared between Night shift and Day shift individuals.
INCLUSION CRITERIA:
1. 30 Nightshift BPO workers.
2. 30 Day shift BPO workers - age and sex matched individuals.
3. Age of individuals between 18 to 55 years.
4. Both the sexes.
EXCLUSION CRITERIA:
1. Individuals with other pre-existing endocrinal diseases, cardiac problems, psychiatric disorders, medical problems (non – diabetic, non – hypertensive).
2. Volunteers who are on any drugs like Amphetamines, Sedatives, Benzodiazepines, CNS Stimulants, Steroids or any other drug that grossly affects the sleep quality or quantity.
PARAMETERS:
1. Age.
2. Sex.
3. Anthropometry (Height, Weight, BMI)
4. Sleeping hours per day assessed by a standard questionnaire.
5. Duration of Employment.
6. Heart rate Variability (Time domain and frequency domain parameters)
7.3 INVESTIGATIONS AND INTERVENTIONS:
Heart rate variability will be calculated by using RMS Vagus HRV software (RMS, India).
Statistical Methods:
Wilcoxon signed ranks test (non – parametric test for 2 related samples) will be used to compare the Heart rate Variability between Night shift and Day shift BPO employees.
7.4 ETHICALCLEARANCE: ENCLOSED
8. LIST OF REFERENCES:
1. Nayantara Santhi et al 2005. Scheduling of sleep/darkness affects the circadian phase of night shift workers. Neuroscience Letters; 384: 316 – 320.
2. Helen J. Burgess et al 2002. Bright light, dark and melatonin can promote circadian adaptation in night shift workers. Sleep Medicine Reviews; Vol. 6, No. 5: 407 – 420.
3. Joao Freitas et al 1997. Circadian Heart Rate Variability Rhythm in Shift Workers. Journal of Electrocardiology; Vol. 30 No. 1: 39 – 44.
4. Ahmad Sajadieh et al 2004. Increased heart rate and reduced heart–rate variability are associated with subclinical inflammation in middle – aged and elderly subjects with no apparent heart disease. European Heart Journal; 25: 363 – 370.
5. Bonnet. M. H et al 1998. Heart Rate Variability in Insomniacs and Matched Normal sleepers. Psychosomatic Medicine; 60: 610-615.
6. Masahiko Kato et al 2000. Effects of Sleep Deprivation on Neural Circulatory Control. Hypertension; 35: 1173 -1175.
7. Emilia Sforza et al 2004. Heart rate activation during spontaneous arousals from sleep: effect of sleep deprivation. Clinical Neurophysiology 115: 2442 - 2451.
8. D A Thomas et al 1996. The effect of sleep deprivation on sleep states, breathing events, peripheral chemoresponsiveness and arousal propensity in healthy 3 month old infants. Eur Respir J; 9: 932 – 938.
9. American Sleep disorders Association. International Classification of sleep disorders, Revised: Diagnostic and coding manual.
10. Xu Zhong et al 2005. Acute sleep deprivation is associated with increased sympathetic and decreased parasympathetic cardiovascular modulation in normal humans. J Appl Physiol; 00620.2004 doi: 10.1152.
9. SIGNATURE OF THE CANDIDATE:
10. REMARKS OF THE GUIDE:
Heart rate variability gives us a good insight into the functions of autonomic nervous system. Its study in sleep deprived young individuals will predict the results of physiological disturbances and provide an insight into their long-term health.
11. NAME AND DESIGNATION OF:
11.1 GUIDE:
Dr. G.JAISRI. MD
Professor, Department of Physiology,
M.S.Ramaiah Medical College, Bangalore-54
SIGNATURE:
11.2 CO-GUIDE:
Dr. VENKATESH.D. MD
Professor, Department of Physiology,
M.S.Ramaiah Medical College, Bangalore.
SIGNATURE:
11.3 HEAD OF THE DEPARTMENT:
Dr. RAJEEV SHARMA. MD
Professor and Head, Department of Physiology,
M.S.Ramaiah Medical College, Bangalore.
SIGNATURE:
12.1 REMARKS OF CHAIRMAN AND PRINCIPAL:
12.2 SIGNATURE: