Effect of obesity on autonomic nervous system

Abstract

The present study was carried out on 100 volunteers of which 50 subjects with BMI > 30kg/m2 were included in study group and 50 subjects with BMI < 30kg/m2 (non obese) were included in control group. The functioning of Autonomic nervous system was evaluated by six non-invasive tests- four of which were based mainly on parasympathetic control (30:15 ratio, standing to lying ratio (S/L ratio), expiration/inspiration ratio (E/I ratio) and valsalva maneuver) and two on sympathetic control (Blood pressure response to standing and cold pressor test). The results of the present study showed significantly low (p=0.001) S/L ratio in study group (1.04 ± 0.12) when compared to controls (1.12 ± 0.11) indicating impaired parasympathetic function. The mean change in sytolic blood pressure before and after cold pressor test (CPT) was less in study group (7.12 ± 5.28) as compared to control group (10.38 ± 6.35) and this was statistically significant (p=0.006) indicating impaired sympatheitc function. Thus ,in obese both division of ANS are affected which may be the cause of various cardiovascular complications.