Losing sleep sucks! I hate it, and I know you do as well. Like most Americans, I have a strong coffee habit to get a swift start to my day. When getting fewer hours of sleep than we planned, we often turn to that extra cup (or 3) to properly carpe diem. We feel like it’s working, but can caffeine really reverse the negative effects of sleep deprivation on endurance performance? It just so happens that a few scientists have taken an interest in this exact topic!
You may have read our research corner article about the differences between staying up late and waking up early. That study featured a cycle sprint test and found negative effects due to sleep deprivation, with early rising having a more negative effect on cycling power output than staying up late. While one was definitely worse than the other, the major point is that both patterns of sleep deprivation reduced performance, and several other studies on cycling have made the same observations.
Investigations on treadmill running time to exhaustion find an average reduction in performance of about 20%! Overall, the science suggests that submaximal work is more impacted by loss of sleep than maximal exercise. This may be due to central fatigue, increased perceived effort (feeling tired vs. actually being tired), decreased muscle glycogen concentrations, or possibly more factors as a result of lack of sleep. However, one thing is abundantly clear. Sleep is our friend, and we do not want to lose her at any price!
The researchers are actually the same group as our other sleep restriction article, yet this time around they added some morning caffeine to the participants routine during one half of the sleep restriction trials. In this study, participants completed a baseline (full) night of sleep or partial sleep (4 hours) prior to completing 2 different supplement trials in a random order. After waking on the 4 separate treatment mornings, participants were provided placebo or 5 mg of caffeine per kg of body weight. Afterwards, they completed a cycle sprint test and an intermittent shuttle test.
Caffeine improved a number of perceptual measures (perceived fatigue, anxiety, etc.), but we already know from experience that caffeine will help with how we feel. Without caffeine, participants peak cycling power output declined by ~10%. However, during the caffeine trial, cycling power output decreased by just 4%, indicating that those with the caffeine preserved 60% of their power output that they would have otherwise lost. During the shuttle test, the placebo condition had an even greater reduction in performance, 13%, yet again, the caffeine trial only experienced a 4% detriment and preserved 70% more of their exercise capacity than those without caffeine. Similar to many other investigations, comparing caffeine vs. placebo on the full night’s sleep alone, caffeine still outperformed the placebo.
Another study examined the effects of 200mg caffeine in soldiers assigned to a sustained operation simulation. Prior to the trial, soldiers completed a 4km obstacle course race for time. Then, over a three day period, soldiers were permitted 4 hours of sleep on only the second and third days (8 hours total over 3 days). They were provided with placebo or 200mg caffeine three times per day throughout each of the three days. The researchers found that soldiers completed the obstacle course 1 minute faster during the caffeine trial than the placebo trial.
You may have suspected caffeine would help athletes who were not getting enough sleep, and you were right! Sleep deprivation is a nasty customer, and one that we cannot always fix just by getting more sleep due to a busy lifestyle, children, travel, etc. Whatever the reason may be, there’s no need to let your performance suffer… At least not by more than 4%! This is just one of the many reasons caffeine is a focal point in PerformElite, which actually has both regular and an extended-release caffeine to get you going quick and keep you quick longer.
Souissi, M., Chikh, N., Affès, H., & Sahnoun, Z. (2017). Caffeine reversal of sleep deprivation effects on alertness, mood and repeated sprint performances in physical education students. Biological Rhythm Research, 1-15.
McLellan, T. M., Kamimori, G. H., Voss, D. M., Tate, C., & Smith, S. J. (2007). Caffeine effects on physical and cognitive performance during sustained operations. Aviation, space, and environmental medicine, 78(9), 871-877.
Fullagar, H. H., Skorski, S., Duffield, R., Hammes, D., Coutts, A. J., & Meyer, T. (2015). Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports medicine, 45(2), 161-186.