Correlation of body mass index and cardiovascular reactivity to exercise-induced stress in young adults

Abstract

Cardiovascular reactivity (CVR) is an increase in heart rate and blood pressure when exposed to stress. Increased CVR to stress is an indicator of developing hypertension. In this study we have tried to understand if exaggerated CVR and obesity are related to each other. Methods Institutional Ethics Committee (Human Studies) clearance was obtained and a convenient sampling of 32 females and 32 males were done based on their age(>18 to <25years), and normotensive status. Baseline blood pressure, heart rate and five minutes finger photoplethysmography was recorded. Pulse wave contour analysis gave the pulse transit time, stiffness index and reflection index. A pedometer was hooked to the waistband of the subject and was asked to walk around the department corridor with an average speed of 100 steps in 1 minute to count 3000 steps in 30 minutes. After 3000 steps, immediate measurement of heart rate, blood pressure, and finger plethysmography for 5minutes was done in supine lying position. Pearson's correlation method and paired t test was done with statistical significance set at p<0.05. Results A positive correlation existed between the BMI and various reactivity measures of the heart rate, systolic blood pressure and diastolic blood pressure .A definite trend of positive correlation was noticed There was an inverse relationship between the BMI and elasticity of the arteries. Conclusion Autonomic nervous system is the most powerful energy saving regulatory system in our body. Failure of this system will lead to deposition of fat in one's body leading to Obesity. Reduced autonomic activity in obese subjects is a risk factor for cardiovascular morbidity.