Official Journals By StatPerson Publication
Table of Content - Volume 6 Issue 3 -June 2018
A study of sympathetic function tests in obese females
Sunita Manikrao Handergulle1, Savita Satyanarayan Somani2*
1Professor and HOD, 2Assistant Professor, Department of Physiology, Swami Ramanand Teerth Rural Medical College, Ambajogai, Maharashtra, INDIA. Email: drsomanisavita@gmail.com
Abstract Background: Obesity is a medical condition in which excess body fat accumulates to an extent that it poses a negative effect on health, leading to decrease in life expectancy and increased health problems, The present study is designed to see the effect of adiposity and body mass index (BMI) on sympathetic function tests to avoid further cardiovascular complications. Aims and Objectives: The aim of the study is to carry out sympathetic function tests in obese females. Materials and Methods: The study was carried out in 50 obese females of BMI >30kg/m2 and W/H ratio >0.85 of age between 30 -40 years. Non Obese females having BMI < 25kg/m2 and W/H ratio< 0.85 were selected. They undergo the sympathetic function tests such as blood pressure (BP), orthostatic variation in BP, and cold pressor test. Statistical analysis was done by student paired t‑test. Result: BMI and W/H ratio were significantly higher in obese females. Response to various sympathetic tests was altered in obese females as compared to non obese females reflecting highly significant increase in the sympathetic activity. Conclusion: Obesity leads to autonomic dysfunction in the form of sympathetic excitation Key Words: Autonomic Nervous System; Body Mass Index (BMI), Waist Hip ratio (W/H ratio), Sympathetic Activity,Obesity
INTRODUCTION Obesity is a serious health problem considered as a global epidemic.1 It has been called as New world Syndrome and is reflection of massive social, economic and cultural problems currently facing developing and developed countries.2 It is suggested that obesity resulted an imbalance between energy intake and expenditure resulting from complex interaction of genetic, physiological, behavioural and environmental factors. In particular, obesity in the female population rapidly increases after middle age. Various explanation put forward for this that reduced basal metabolic rate due to lack of physical activity, decrease in the growth hormone and oestrogen, and overeating.3 Chronic exposure to environmental stress may play a role in the development of obesity through hyperactivation of the hypothalamo-pituitary-adrenocortical axis.4, Abdominal obesity and its metabolic consequences are significantly correlated with stress related conditions.5 It is mentioned that one or more sub groups of obesity have an alteration in their autonomic nervous system (ANS) that may promote obesity.6 ANS of obese individuals is chronically altered.7,8 It is frequently said that the purpose of the sympathetic system is to provide extra activation of the body in states of stress this is called as the sympathetic stress response.9 Very less research studies available for stress response (sympathetic function tests) in obese females. Hence in this research work we have studied the sympathetic function tests in obese female to assess the stress response in them. MATERIALS AND METHODS The study of sympathetic function tests was carried out in 50 obese and equal number of non obese female volunteers between the age group of 30-40 years from general population of town area. All were from the middle socioeconomic class. The approval for the study was obtained from Institutional Ethics committee. Exclusion Criteria Volunteers All the volunteers were assessed for sympathetic function tests during proliferative phase. All tests were carried out in the morning hours. They were asked to abstain from tea or coffee for 12 h before the procedure. Before starting the procedure, physical examination of all the females was done with the help of predesigned proforma and written informed consent form was signed by all of them. The procedure was explained to all participants to alleviate fear. Blood pressure (BP) was recorded with sphygmomanometer by auscultatory method. After giving rest for 5 min, the following parameters were recorded. Sympathetic Function Tests11
The body mass index (BMI) was calculated as 10 BMI = weight (in kilograms) height (in square meters) Waist –Hip ratio (W/H ratio) was calculated as10 W/H ratio = Waist circumference at the level of iliac crest Hip circumference at the fullest point around buttocks Selection Criteria for obese females10
Selection Criteria for non obese females 10
Statistical Analysis: It was done by student paired t‑test. P < 0.05 was considered as statistically significant. The software used for it is Graph pad Prism 5. OBERVATIONS Table 1: Comparison of BMI and W/H ratio in obese and non obese females
BMI: Body Mass Index, W/H ratio: Waist Hip ratio
Table 2: Comparison of sympathetic function tests in obese and non obese females
SBP: Systolic blood pressure, DBP: Diastolic blood pressure, SD: Standard deviation RESULTS In Table 1 BMI and W/H ratio was compared in obese and non obese females. It was seen that BMI and W/H ratio were statistically highly significant (P < 0.001) in obese females as compared to non obese females. In Table 2 sympathetic activity was compared in obese and non obese females. It was observed that BP, orthostatic variation in arterial BP, and cold pressor test were statistically highly significant (P < 0.001) in obese females.
DISCUSSION In the present study, responses to BP, orthostatic variation in arterial BP, and cold pressor test were significantly (P < 0.001) altered in obese females as compared to that of non obese females, reflecting a significant increase in sympathetic activity. Won-Mok Son et al3 also showed the increased systolic and diastolic BP. Simon G et al12 in their study found the significant variation in systolic blood pressure during cold pressor test. Diastolic BP and orthostatic response were significantly higher in obese group. As per Uppalapadu Sudarsana et al13 diastolic blood pressure and orthostatic response were significantly higher in the obese group Simran Grewal2 found the impaired sympathetic response in obese subjects. Middle age causes the onset of the gradual decline of physical activity and women become vulnerable to obesity, hypertension, and cardiac disease. The body secretes less estrogen which promotes fat accumulation leading to obesity. This lead to dyslipidemia and increase the risk of coronary artery disease.14,15 Increase in body fat percentage and triglycerides in obesity leads to an elevated blood lipid concentration, which affects vascular stiffness. Increased arterial stiffness causes elevated pulse pressure, increasing the afterload on the heart,16 Arunima Chaudhuri et al17 mentioned that Indians have a higher percentage of body fat for a given BMI compared with the white Caucasians and African-Americans but have a lower muscle mass.. Insulin resistance., diabetes, hypertension and hyperlipidemia in women are linked strongly to intra-abdominal or upper body fat than to overall adiposity. W/H ratio has been found to be more predictive than abdominal obesity.18,19 Human obesity is characterized by marked sympathetic activation. 16Increased sympathetic activity induced by cold water stress causes non epinephrine release and elevation of BP. It was seen that forearm vascular resistance is significantly higher in obese individuals when compared with the lean individuals during sympathetic excitation induced by CPT which indicates autonomic instability.20 The increase in BP might be also due to more release of endothelins, prostaglandins and angiotensin II.21 Prema joshi22 in their study observed that obesity is one of the reason for enhanced sympathetic response in postmenopausal women. Thus it seems that obesity itself is a stress in the form of enhanced sympathetic function tests response. Implications: Although women of the present study did not complain of any physical or psychological symptoms yet significantly increased sympathetic activity responses indicate an increased stress.
LIMITATIONS Further study with large samples is required to correlate autonomic nervous system (ANS) functions with body fat percentage.
CONCLUSION Obesity itself acts as physical and mental stressful condition resulting in autonomic dysfunction in the form of sympathetic excitation. So body weight must be controlled by dietary management, regular exercise, yoga, meditation and pranayam to relive that stress complication.
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