Restless: The Impact of Sleep Deprivation on Racing and Training

You’ve put in months of hard work training, fine-tuning your equipment, your nutrition, and your race strategy, and you feel prepared to crush your goal event. But the night before, nervous excitement keeps you up, with a growing sense of panic over your inability to fall asleep. Is your big day ruined?

For more on sleep deprivation and training, check out Ask A Cycling Coach Ep 300.

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If you’re an endurance athlete, there’s a good chance you’re familiar with pre-race sleeplessness. It’s all-too-common the night before big events, intimidating workouts, and even before exciting rides with friends. And it’s not limited to amateurs, as even professional athletes often find themselves tossing and turning in anticipation the night before major races. It’s probably not a disaster for your goal event, but sleeping well could be the key to staying healthier and getting faster.

The Benefits of Sleep

Sleep is essential for human health, involved in every aspect of your well-being- from hormone regulation and immune function to emotions and cognitive capacity. For athletes, sleep is even more important, allowing your body to recover and develop new capabilities. In fact, it’s largely during sleep that your muscles grow and develop in response to training stress. In other words, you get faster when you sleep.

But for something so important and innate to our lives, far too many of us aren’t sleeping enough. Experts recommend at least 7-9 hours for adults, with athletes generally thought to require even more. And yet the CDC reports more than a third of American adults regularly don’t get enough sleep, and some studies suggest poor sleep might be even more common among athletes than the general public. If you’re not getting enough sleep, you’re not alone, but that doesn’t mean it’s a good thing for your racing, training, and overall health.

The Consequences of Sleep Deprivation 

Sleep deprivation is a major threat to public health. According to Johns Hopkins, long-term effects include increased risks of high blood pressure, heart disease, and dementia. People who don’t get enough sleep get sick more, experience higher rates of mental illness, and are more likely to suffer accidents or injuries due to drowsiness than folks who sleep 7 or more hours per night. Additionally, hormonal effects mean sleep-deprived individuals have trouble controlling cravings for sweet and salty foods, nearly tripling the risk for type 2 diabetes over the well-rested. 

Training Tired

For athletes, sleep deprivation can directly interfere with the ability to train and get faster. One alarming example is immune function. While exercise is generally beneficial to the immune system, hard training is taxing and can temporarily reduce immunity, and chronic sleep restriction significantly confounds this effect. In one study of 153 adults over two weeks, those sleeping less than 7h per night were almost 3x more likely to develop infections than those who slept more than 8h; another study found that adults sleeping less than 5h were 4.5x more likely to get sick. Coupled with a resulting increase in pro-inflammatory cytokines, sleep deprivation may be an invitation to illness, and you can’t train if you’re sick.

Athletes who don’t get enough sleep experience poor muscle glycogen replenishment, potentially limiting their capacity for upcoming endurance efforts. Also, reductions in growth hormone secretion and muscle protein synthesis mean a tired body does less structural repair to the muscles themselves, meaning the same training may have less effect in fatigued athletes. 

Finally, multiple studies have demonstrated an increased risk of injury among tired athletes. It’s unclear whether this is due to physical fatigue or a decrease in reaction time, but the greatest risk seems to occur when training load increases and sleep decreases. If you’re chronically short on rest, an increase in training may be counterproductive to your health in more ways than one.

Chronic vs. Acute Fatigue

Not all fatigue is created equal, and most of these ominous consequences are associated with chronic sleep deprivation- defined as getting less rest than needed for several weeks or more. Luckily for athletes, acute sleep deprivation- a night or two of bad sleep here and there- does not seem to carry such dramatically deleterious effects.

This is not to say that acute sleep deprivation is without impact, but studies suggest the resulting costs may be more psychological than physiological. Specifically, a bad night of sleep may increase your rate of perceived exertion (RPE) without actually impacting your physical ability to perform. Other studies show that a major effect of sleep deprivation is a negative impact on self-control, and taken together these two factors hint at one way a bad night of sleep might hold you back. If an effort feels harder and you’re less able to motivate yourself to push through the pain, your performance could decrease- even if your physical capabilities are unaffected. 

So You Slept Poorly Before Your Race… Now What?

There’s a well-known saying that how you sleep the night before your race matters less than how you sleep two nights before, and there’s probably an element of truth to this. A single night of acute sleep deprivation is unlikely to result in serious negative effects, but a chronic shortage of rest will almost definitely take a toll. Do yourself a favor and get better sleep in training and during the run-up to your event, and one restless night will be less likely to ruin your goals.

And if you do sleep badly the night before a big day, remember that the most significant impact is likely to be in cognition and in how you perceive your effort, rather than what you are actually capable of. This means that disciplines that require a high degree of focus and concentration, such as mountain bike races, criteriums, and time trials, might be more likely to suffer as a result of acute bad sleep. Luckily, alertness and RPE are relatively easy to influence- the excitement and adrenaline of race day do this automatically for many athletes, and caffeine can help, as well. 

Prioritize Rest

Any steps you can take to improve your sleeping habits can have a significant positive impact, and for many athletes improved rest is the single biggest factor in breaking through plateaus. By prioritizing rest, you can stay healthier, see bigger results from your training, and have more leeway when it comes time for the inevitable restless night before a big race. 

References/ Further Reading

Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB. Sleep habits and susceptibility to the common cold. Arch Intern Med. 2009 Jan 12;169(1):62-7. doi: 10.1001/archinternmed.2008.505. PMID: 19139325; PMCID: PMC2629403.

Fullagar H, Skorski S, Duffield R, Hammes D, Coutts A, Meyer T. (2014). Sleep and Athletic Performance: The Effects of Sleep Loss on Exercise Performance, and Physiological and Cognitive Responses to Exercise. Sports Medicine. 45. 10.1007/s40279-014-0260-0.

Kirschen G, Jones J, Hale L. (2018). The Impact of Sleep Duration on Performance Among Competitive Athletes: A Systematic Literature Review. Clinical Journal of Sport Medicine. 30. 1. 10.1097/JSM.0000000000000622.

Pilcher JJ, Morris DM, Donnelly J, Feigl HB. Interactions between sleep habits and self-control. Front Hum Neurosci. 2015 May 11;9:284. doi: 10.3389/fnhum.2015.00284. PMID: 26029094; PMCID: PMC4426706.

Prather AA, Janicki-Deverts D, Hall MH, Cohen S. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. Sleep. 2015 Sep 1;38(9):1353-9. doi: 10.5665/sleep.4968. PMID: 26118561; PMCID: PMC4531403.

Saner N, Lee M, Pitchford N, Kuang J, Roach G, Garnham A, Stokes T, Phillips S, Bishop D, Bartlett J. (2020). The effect of sleep restriction, with or without high-intensity interval exercise, on myofibrillar protein synthesis in healthy young men. The Journal of Physiology. 598. 10.1113/JP278828.

Sargent C, Halson S, Roach G. (2014) Sleep or swim? Early-morning training severely restricts the amount of sleep obtained by elite swimmers, European Journal of Sport Science, 14:sup1, S310-S315, DOI: 10.1080/17461391.2012.696711

VanHelder T, Radomski MW. Sleep deprivation and the effect on exercise performance. Sports Med. 1989 Apr;7(4):235-47. doi: 10.2165/00007256-198907040-00002. PMID: 2657963.

Watson AM. Sleep and Athletic Performance. Curr Sports Med Rep. 2017 Nov/Dec;16(6):413-418. doi: 10.1249/JSR.0000000000000418. PMID: 29135639.