Effect of rhythmic handgrip exercise on cardiovascular system in otherwise healthy obese subjects

Introduction: Obesity is a topic of increasing concern and is associated with decreased physical activity. Some dysregulation in a mechanism causing cardiovascular, and hemodynamic adjustments during exercise (Meta boreflex; a feed-back mechanism originating in skeletal muscle due to local metabolites) has been demonstrated in obese subjects. Aims and objective: The purpose of this study is to see the effect of metaboreflex by rhythmic handgrip exercise on hemodynamic parameters (Blood pressure(BP), cardiac output(CO)/index(CI), stroke volume(SV)/index(SVI), pulse rate(PR), systemic vascular resistance(SVR)/index(SVRI)) in subjects with obesity. Method and Materials: A total of 26 subjects, aged between 25 to 45 years were enrolled in this study and classified into a) subjects(18 in number) with normal or overweight BMI, and b) subjects(8 in number) with obese BMI. Hemodynamic parameters were evaluated by impedance cardiovasography in supine position, after 5 minutes of rest. Maximum Voluntary Contraction was measured by Handgrip Dynamometer. Rhythmic handgrip exercise was done at 30% of the subjects’ MVC (for 2 mins), followed by post exercise cuff occlusion to enhance metaboreflex, for 2 mins (20 mm Hg above systolic). Parameters were assessed post rhythmic exercise. Results: Following exercise, there was vasoconstriction mediated pressor response (statistically significant increase in diastolic BP) and flow mediated pressor response (statistically significant increase in systolic BP) in normal subjects. In subjects with obese BMI, there was a statistically significant reduction in SVR and therefore a reduction in vasoconstriction mediated pressor response. Decrease in SVR also caused an increased flow mediated response (CO). Conclusion: In this study, it can be concluded that obese BMI decreases vasoconstriction response due to Metaboreflex and therefore Metaboreflex can act as a predictor of cardiovascular risks in obesity.