Caffeine intake helps maintain 3-km cycling performance the morning following sleep restriction

Abstract Introduction: Although a full understanding of the role of sleep is debated, it is widely accepted that sleep is important for recovery from heavy exercise. Recent research suggests that sleep restriction (SR) may negatively impact recovery and subsequent performance. It is unknown if caffeine supplementation mitigates this performance decrement. Our objective was to investigate the effect of caffeine supplementation on exercise performance following one night of SR in trained cyclists. Methods: Subjects (n=10) completed a 3-km time trial (TT) and an exhaustive bout of exercise in the evening (EX1), then returned to repeat the TT the following morning (EX2). Exercise trials were separated by a full night of sleep (FULL) or a night of restricted sleep (SR). Perceived fatigue was also assessed prior to EX2. Caffeine (CAF) or placebo (PLA) treatments were given before the start of EX2. A randomly counterbalanced, double blind, placebo controlled design was used to compare the effects of four different treatment conditions: FULL/PLA, SR/PLA, FULL/CAF, SR/CAF. Results: Data were analyzed using magnitude-based inferences to compare differences in EX2 performances only. Power output was ‘possibly’ greater (0.9 ± 3.6%) following SR/PLA compared to FULL/PLA. Power output was ‘likely’ higher (5.5 ± 4.8%) following SR/CAF compared with SR/PLA. Perceived fatigue was rank ordered as 1) SR/PLA, 2) SR/CAF, 3) FULL/PLA, 4) FULL/CAF. Specifically, CAF ‘very likely’ reduced perceived fatigue following SR compared to SR PLA, but remained ‘likely’ higher than FULL/CAF. Conclusion: These data show that caffeine has the ability to mitigate performance decrements resulting from a single night of SR following heavy exercise. Caffeine also prevented increases in perceived fatigue following SR