Running on No Sleep: How it Effects Performance on Race Day and in Training
Last week, we saw how the time of day can affect your performance. Because of the way your body’s core temperature is modulated over the course of each 24-hour day, athletic performance appears to be enhanced in the late afternoon and evening, and diminished in the early morning. This phenomenon is no stranger to anyone who’s rolled out of bed and tried to get the day’s workout in before work.
But, another reason morning workouts can be such a pain is sleep deprivation, the subject of today’s article.
You already know that you’re supposed to get 7-9 hours of sleep every night, but for most Americans, that isn’t happening on a regular basis. Going to work on a few hours’ sleep can leave you feeling tired and slow to react, but what is the effect of running on no sleep on athletic performance, and can anything be done to ameliorate them?
The research on lack of sleep and performance
Surprisingly, sleep deprivation is not a heavily-studied area when it comes to endurance sport performance. A boatload of studies have looked at acute or total sleep deprivation —staying awake for 36 hours continuously, for example—and how that affects decision-making, reaction time, and cognitive ability, as these are all relevant to the military, police, and transportation industries (all of these factors, by the way, show marked declines with progressive lack of sleep).
A few military-funded studies have also looked into chronic partial sleep deprivation, like only getting 5 hours of sleep for several nights in a row, as this is also a topic of interest to big players in physiology research like the military. But there are only a few direct, well-designed studies on how running or other endurance sports are affected by sleep deprivation, so weaving together the separate pieces of indirect evidence is quite a tough task.
Sleep and race performance
Fortunately, a 2007 review paper by Thomas Reilly and Ben Edwards at the Research Institute for Sport and Exercise Sciences at Liverpool John Moores University in the United Kingdom intertwined some of these studies and helped us shed some light on the subject for athletes.
Reilly and Edwards sifted through a variety of studies on exercise performance after both long bouts of being awake and several days’ worth of restricted sleep at night. As we might’ve guessed, sleep-deprived athletes make more errors, worse tactical decisions, and are less resistant to fatigue in repeated high-power bouts of exercise like multiple sets of weight lifts.
But interestingly, physiological markers of endurance performance were surprisingly stable: oxygen demand at various speeds on a treadmill, for example, does not seem to be significantly affected by a few days’ worth of poor sleep.
This might not be such a shock to some veteran runners who’ve set personal bests after tossing and turning the night before the race. For example, John Gregorek, an Olympic steeplechaser, once told me that he didn’t get a wink of sleep before either of his Olympic Trials qualifying races – both of which were PRs
But what’s the upside of this? Can you train just the same when you skimp on sleep?
While Reilly and Edwards’ review found that the body can physiologically perform at the same level when sleep deprived as when rested, they also found that it doesn’t like to.
So, while you may not consume any more oxygen when running at a given pace when tired, you’ll perceive that you are working harder than you would if you were rested.
Across multiple studies, subjects rated their perceived efforts higher when sleep-deprived. Reilly and Edwards suggest that this may be because the brain and the nervous system are the biological structures that need sleep the most: while your heart, lungs, and legs are ready to go at full-tilt even when sleep deprived, your brain and its neural system are sluggish and tired.
Lack of sleep and overall health and training
One area that Reilly and Edwards did not cover in as much detail is the effect of chronic sleep deprivation on general health and well-being. This was addressed by a landmark study by Karine Spiegel, Rachel Leproult, and Eve Van Cauter in a 1999 article that’s been cited over 1500 times since its publication.Speigel et al. used eleven young men restricted to four hours of sleep for six nights in a row. A range of hormonal and metabolic markers were measured throughout the course of every day.
Troublingly, the young men, all between 18 and 27 years old, showed a trend towards a swath of undesirable metabolic and hormonal changes throughout the week. Levels of cortisol, the “stress hormone” connected with overtraining in runners, increased markedly, and glucose tolerance dropped.These signs are all classically associated with aging.
At the end of the week, the subjects who had poor sleep for six nights in a row exhibited hormonal levels that could have been mistaken for those of a 50 or 60-year old!
Fortunately, these changes were reversible after several days of extra sleep. Similar investigations have also showed that chronic sleep deprivation is linked to a drop in your immune system’s ability to fight off infection, hinting that training on little sleep is putting you at risk for a cold or sinus infection.
Happily, the science turns out a little bit in our favor this time around. We all know that, as athletes, we really ought to get eight or even nine hours of sleep every night, and the science backs that up.
- Fortunately for those of you who have to stay up late on occasion before a morning workout, or who can never seem to calm pre-race nerves the night before a competition, missing some sleep won’t affect your physiological fitness in the short-term.
- You should be aware that your perceived effort may be somewhat higher than it would be if you were rested. This can likely be countered by consuming about a cup of coffee’s worth of caffeine 60-90 minutes before your workout or race. Caffeine has the physiological effect of nudging your performance slightly faster, and stimulates your neuromuscular system to boot. Just don’t view your morning coffee as an excuse to skip out on sleep on a regular basis: it will do nothing to prevent you from getting sick, injured, or overtrained because of your body’s inability to recover! And a chronically elevated perceived exertion level will not help your workouts.
- Reilly and Edwards also provide one minor tip for getting through a day without as much sleep as you’d like: consume more carbohydrates. Staying awake for longer necessitates more energy, and hopefully consuming some extra calories can hold you over until you can get a full night’s sleep.
- Finally, always do your best to repay any “sleep debt” you incur. Several long nights or early mornings in a row can make your hormonal profile age by decades, so make sure you get extra sleep to reverse that effect.