Capsaicinoid and Capsinoids as an Ergogenic Aid: A Systematic Review and the Potential Mechanisms Involved.

CONTEXT: Capsaicinoids and capsinoids (CAP) are natural substances found primarily in chili peppers and other spicy foods that agonize the transient receptor potential vanilloid-1 in the mouth, stomach, and small intestine. Several studies have shown CAP to be a potential antiobesity agent and to exhibit an analgesic effect in both rodents and humans. However, there is no scientific consensus about the effects of CAP on physical exercise performance and its physiological mechanisms of action. PURPOSE: This systematic review aimed to better elucidate the effects of CAP compounds as ergogenic aids and to discuss underlying mechanisms of action by which this supplement may potentially enhance endurance performance and muscular strength. CONCLUSIONS: Among 22 studies included in the review, 14 examined the effects of capsaicinoid or capsinoid compounds on endurance and resistance exercise performance in animals, with 9 studies showing benefits on performance. In humans, 8 studies were included: 3 demonstrated significant acute endurance benefits and 2 showed acute resistance exercise performance benefits compared with a placebo condition. Therefore, while more mechanistic studies are necessary to confirm these outcomes in humans, the available scientific literature appears to suggest that these compounds could be considered an effective nutritional strategy to improve exercise performance.

Beta-Alanine Supplementation Improved 10-km Running Time Trial in Physically Active Adults.

The purpose of this study was to investigate the effects of ß-alanine supplementation on a 10 km running time trial and lactate concentration in physically active adults. Sixteen healthy subjects were divided randomly into two groups: ß-alanine (n = 8) and placebo group (n = 8). The experimental group ingested 5 g/day of ß-alanine plus 1 g of resistant starch, and control group ingested 6 g of resistant starch, both for 23 days. Time to complete a 10-km running time trial and lactate concentration following the test were assessed at baseline and post 23 days. The running training program was performed three times per week on non-consecutive days (day 1: running 7 km; day 2: six sprints of 500 m at maximum speed with 2 min of recovery; day 3: running 12 km). The time to complete a 10-km running time trial decreased significantly only for the ß-alanine group (Pre = 3441 ± 326.7, Post = 3209 ± 270.5 s, p < 0.05). When analyzing the delta (Time post minus Time at baseline value) there was a statistically significant difference between the ß-alanine vs placebo group (-168.8 ± 156.6 vs. -53.60 ± 78.81 s, p = 0.007), respectively. In addition, the ß-alanine group presented lower blood lactate concentration after the 10-km test (ß-alanine: Pre = 8.45 ± 1.94 vs. Post = 6.95 ± 2.44 mmol/L; Placebo: Pre = 8.7 ± 3.0 vs. Post = 10.8 ± 2.5 mmol/L, p = 0.03). In conclusion, ß-alanine supplementation improved the 10-km running time trial and reduced lactate concentration in physically active adults.