Effect of Withania somnifera on physical and cardiovascular performance induced by physical stress in healthy human volunteers

Abstract

Background: Withania somnifera (WS) rejuvenates, increases vigour, vitality and immunity. The antistress effects of WS on physical performance and cardiovascular parameters during exercise were evaluated in healthy volunteers. Methods: Prospective, open label, randomized, placebo controlled, comparative, pilot study was designed in healthy adult volunteers. After Ethics committee approval 30 consented participants were randomly assigned into three equal groups to receive single capsule for 28 days containing maize starch (placebo group), WS aqueous extract 330mg (WS 330 gr) and 500mg (WS 500 gr). They were assessed at day 0, day 14, day 28 with physical stressors (six minute exercise test, YMCA Submaximal Test, Fixed workload exercise on cycle ergometer), Jammers' hand held dynamometer test and cold pressor test in each visit. Physical performance was evaluated as maximum distance, speed, oxygen consumption, hand grip strength. Cardiovascular response was assessed by heart rate and blood pressure measurements. Results: On day 28, both WS 330 and WS 500 groups showed significant increase in mean distance travelled and average speed compared to placebo (p<0.005). WS 330 and 500 groups showed significant decrease in mean systolic BP on fixed workload exercise, compared to placebo (p<0.05). Conclusions: WS increased physical performance when participants were subjected to physical stress but it did not increase the activity of sympathetic system thus contributing to its anti-stress activity.