About Athletes: Caffeine and Sleep

The effects of caffeine on sleep and behavior after sleep deprivation have been widely reported. Sleep is considered an important component of athletes' physiological and psychological recovery from high-intensity training and preparation for high-intensity training. Long-term mild to moderate sleep deprivation in athletes (possibly attributable to caffeine intake) may negatively affect or alter glucose metabolism, neuroendocrine function, appetite, food intake and protein synthesis, as well as attention, learning, and memory. These factors can all negatively affect athletes' nutritional, metabolic, and endocrine status, potentially affecting energy levels, muscle repair, immunity, body composition, memory, and learning ability, leading to decreased athletic performance.

Although caffeine intake may affect sleep quality, the timing of caffeine intake may determine the frequency of these negative effects. For example, in a study involving 13 participants, morning caffeine intake negatively affected sleep in only one participant. However, late afternoon (18:00) caffeine intake caused insomnia in 6 participants. These results can most likely be explained by caffeine's half-life, which is generally about 4 to 6 hours (although there are individual differences). To avoid negative effects on sleep, athletes may consider consuming caffeine as early as possible in the day. There are also reports of significant individual differences, where functional genetic polymorphisms are associated with individual sensitivity to sleep disruption and caffeine effects after sleep deprivation.