Roselle ( Hibiscus sabdariffa L.) calyces tea improves physical fitness of healthy adults

Abstract

Roselle calyces ( Hibiscus sabdariffa L.) is a plant that contains anthocyanin and flavonoids, which function as exogenous antioxidants for the human body to counteract excess oxidative stress. Roselle has anti-hypertensive, anti-cancer and anti-diabetic effects. The present study evaluated roselle to see whether it affects physical fitness. The components of physical fitness include strength, balance, right and left hand grip, vertical jump and VO _2max (maximum oxygen consumption). A total of 30 subjects received 200 ml rosella tea for 30 days every morning and evening. Every week, subjects were assessed for physical fitness. Data analysis used paired t and Wilcoxon test according to the normality test results. The results showed significant improvements in strength (from 24.9 to 27.3 kg; P=0.025), balance (from 23.3 to 42.2 sec; P=0.004), right (from 31.8 to 35.1 kg; P<0.0001) and left hand grip (from 29.8 to 31.6 kg; P=0.020), vertical jump (from 38.6 to 41.1 m/sec; P=0.008) and VO _2max (from 31.1 to 34.3 ml/kg/min; P=0.014). This demonstrated that roselle significantly improved six parameters of physical fitness and may be used as a supplement to improve physical fitness without severe side effects.