Effects of Kaempfera parviflora Supplementation on the Cardiovascular Endurance of Athletes: A Randomized, Placebo Controlled, Parallel Design Study

Abstract

Background: Kaempfera (K.) parviflora (i.e., Thai ginseng) is believed to have medicinal properties associated with good health (e.g., increased vitality, metabolism booster) because it expands blood vessels, which allows for increased blood flow. These effects might extend into the realm of improving physical performance, specifically that of the cardiovascular system. Objectives: A randomized, placebo-controlled, parallel design study was conducted to determine the effects of 12 weeks of K. parviflora supplementation on the cardiovascular endurance of healthy male adults. Methods: Participants included 57 Thai air force cadets who were undergoing physical training for sports competition. Participants were randomly divided into either the treatment group (n = 30) (Age = 20.30 + 0.65 yrs.) or control group (n = 27) (Age = 20.37 + 0.68 yrs.). Treatment group participants received 360 mg of K. parviflora extract in capsule form, and those in the control group received a placebo capsule. Measurements included lactate threshold and heart rate recovery, assessed at baseline and weeks 6 and 12. Group differences were assessed using a 2 (group) × 3 (time) repeated-measures ANOVA. Results: No main or interaction effects were observed for the lactate threshold (all P > 0.05). No group differences were observed for heart rate recovery (P > 0.05); however, a significant time effect was observed for heart rate recovery at weeks 6 and 12 (P < 0.05), which also marked the beginning of an interaction effect showing that those in the experimental group improved more than those in the control group (P > 0.05). Conclusions: In this set of observations, 12-weeks of K. parviflora supplementation had no effect on the lactate threshold; however, it does appear that it might have improved heart rate recovery.