No additive effect of creatine, caffeine, and sodium bicarbonate on intense exercise performance in endurance‐trained individuals

Background Athletes commonly use creatine, caffeine, and sodium bicarbonate for performance enhancement. While their isolated effects are well‐described, less is known about their potential additive effects. Methods Following a baseline trial, we randomized 12 endurance‐trained males (age: 25 ± 5 years, VO2max: 56.7 ± 4.6 mL kg−1 min−1; mean ± SD) and 11 females (age: 25 ± 3 years, VO2max: 50.2 ± 3.4 mL kg−1 min−1) to 5 days of creatine monohydrate (0.3 g kg−1 per day) or placebo loading, followed by a daily maintenance dose (0.04 g kg−1) throughout the study. After the loading period, subjects completed four trials in randomized order where they ingested caffeine (3 mg kg−1), sodium bicarbonate (0.3 g kg−1), placebo, or both caffeine and sodium bicarbonate before a maximal voluntary contraction (MVC), 15‐s sprint, and 6‐min time trial. Results Compared to placebo, mean power output during 15‐s sprint was higher following loading with creatine than placebo (+34 W, 95% CI: 10 to 58, p = 0.008), but with no additional effect of caffeine (+10 W, 95% CI: −7 to 24, p = 0.156) or sodium bicarbonate (+5 W, 95% CI: −4 to 13, p = 0.397). Mean power output during 6‐min time trial was higher with caffeine (+12 W, 95% CI: 5 to 18, p = 0.001) and caffeine + sodium bicarbonate (+8 W, 95% CI: 0 to 15, p = 0.038), whereas sodium bicarbonate (–1 W, 95% CI: −7 to 6, p = 0.851) and creatine (–6 W, 95% CI: −15 to 4, p = 0.250) had no effects. Conclusion While creatine and caffeine can enhance sprint‐ and time trial performance, respectively, these effects do not seem additive. Therefore, supplementing with either creatine or caffeine appears sufficient to enhance sprint or short intense exercise performance.