Abstract
The aim of the present study was to investigate the effects of caffeine ingestion on cognitive and physical performances after 36 h of sleep deprivation. In randomized order, thirteen healthy male physical education students (age: 21.1 +/- 1.1 years, body mass: 77.1 +/- 7.2 kg, height: 1.77 +/- 0.06 m) completed four test sessions at 18:00 h: after placebo or 5 mg.kg(-1) of caffeine ingestion during a baseline night (RN) (bed time: from 22:30 h to 07:00 h) or a night of 36 h of sleep deprivation (TSD). During each test session, participants performed the squatjump (SJ), the reaction time, and the 30-s Wingate tests (i.e., for the measurement of the peak (PP) and mean (MP) powers and the fatigue index (FI)). The results showed that PP and MP decreased and FI increased during the TSD compared to RN in the placebo condition (p < 0.001). The caffeine ingestion improved PP after TSD compared to RN (p < 0.001). SJ decreased significantly after the TSD compared to RN after both placebo and caffeine ingestions (p < 0.001). However, SJ increased significantly after caffeine ingestion during RN and TSD (p < 0.001). The reaction time increased significantly after TSD compared to RN (p < 0.001). However, the reaction time decreased significantly after the caffeine ingestion only during the TSD (p < 0.001). Therefore, caffeine is an effective strategy to counteract the effect of 36 h of sleep loss on physical and cognitive performances. (C) 2014 Elsevier Inc All rights reserved.