Capsaicin supplementation increases time to exhaustion in high-intensity intermittent exercise without modifying metabolic responses in physically active men.

ABSTRACT

PURPOSE: The purpose of this study was to investigate the acute effect of capsaicin supplementation on performance and physiological responses during high-intensity intermittent exercise (HIIE). METHOD: Thirteen physically active men (age = 24.4 ± 4.0 years; height = 176.4 ± 6.9 cm; body mass = 78.7 ± 13.8 kg; running training per week = 3.9 ± 0.9 h) performed an incremental running test to determine peak oxygen uptake ([Formula see text]) and the speed associated with [Formula see text] (s[Formula see text]). Thereafter, subjects completed two randomized, double-blind HIIE (15s15 s at 120% s[Formula see text]) trials 45-min after consuming capsaicin (12 mg) or an isocaloric placebo. Time to exhaustion, blood lactate concentration, oxygen consumption during and 20 min post-exercise, energy expenditure, time spent above 90% of [Formula see text], and the rate of perceived exertion were evaluated. RESULTS: There was no difference between capsaicin and placebo for any variable except time to exhaustion [capsaicin 1530 ± 515 s (102 efforts) vs placebo 1342 ± 446 s (89 efforts); p < 0.001]. CONCLUSION: In conclusion, capsaicin supplementation increased time to exhaustion in high-intensity intermittent exercise without modifying the metabolic response of exercise or the rate of perceived exertion in physically active men. Capsaicin could be used to increase the training load during specific exercise training sessions.