Here’s a scenario a ton of athletes experience, but few talk about: The night after finishing a big endurance competition or a long and strenuous workout, you lie awake in bed or toss and turn despite being thoroughly exhausted. Your sleeplessness may be compounded by feeling like you are radiating heat or you can feel/hear your heartbeat. And even if you are able to get to sleep initially, you struggle to stay asleep and fail to have a restful night. What gives? How can an exhausting event leave you sleepless?
There isn’t one simple cause for post-exercise insomnia, but there are definitely factors that contribute to it:
Exercise ramps up your heart rate, core temperature, and sweat rate. It also has an excitatory effect on your nervous and endocrine systems. The more strenuous the exercise and the longer the workout or competition, the longer you have been in this excited or aroused state. Two of the hormones that appear to play a significant role in post-workout sleep disturbances are norepinephrine and cortisol.
Cortisol is released in response to stress, which means elevated cortisol levels are a natural consequence of exercise. This increase isn’t all bad; it contributes to the training stimulus that drives positive adaptation. However, when an athlete’s training workload is too high and someone is struggling to recover from workouts, chronically elevated cortisol levels are likely part of the problem.
On a day to day basis your cortisol levels fluctuate naturally on a cycle which peaks about 30-minutes after you wake up and slowly declines throughout the day. As a result, you are normally at the lower portion of the cycle when you go to sleep at night. A day-long endurance competition like the Leadville 100, Dirty Kanza 200, or an Ironman pushes cortisol levels up and out of sync with the normal daily cycle for cortisol, which can contribute to sleeplessness.
What about shorter workouts or events? A shorter event closer to your bedtime can have a similar effect to a longer event that ends further before bedtime. What matters are the magnitude of the exertion and the time between the finish and bedtime. The good news for athletes who train in the afternoon or evening is that you can habituate to a routine and essentially train yourself to get to sleep after a workout. Post-exercise insomnia is more common when the magnitude of the exertion is greater than normal for you, or the workout/competition is later in the day than you are used to.
Norepinephrine and Adrenaline
Exercise and competition are exciting, and as a result you release more adrenaline and norepinephrine. Adrenaline levels fall quickly after exercise, but according to a 2011 study by Shahsavar norepinephrine levels may stay elevated for up to 48 hours after exhaustive exercise. This may help explain why some athletes can train in the evening and normally sleep fine, but struggle after exceptionally difficult training sessions and/or very long competitions.
Many athletes consume foods or drinks that contain caffeine before or during workouts and competitions. Caffeine is a stimulant you can habituate to quite readily, meaning that some people can drink coffee late in the day and fall asleep just fine. However, if you are a person who struggles to sleep following a late afternoon/evening workout or after long endurance events, take a look at how much caffeine you are consuming and when you are consuming it. In the case of long events, you may realize that you are ingesting a whole lot more caffeine than you normally would over the course of 10+ hours. If that’s a problem, reserve the caffeinated sports nutrition products for when you will benefit most from increased focus and alertness.
Dehydration and Core Temperature
There isn’t too much you can do to change your hormonal response to exercise (although, being more fit and less stressed out will help), but you can absolutely influence your hydration status and its impact on your core temperature. Your body temperature dips slightly during restful sleep and starts to increase again as you awaken. People also sleep better in cooler environments compared to hot ones. When your body temperature remains elevated you are very likely to have trouble sleeping. Exercise elevates body temperature, and cooling the body becomes increasingly difficult when you are inadequately hydrated. Some level of dehydration is highly likely following long endurance events lasting more than 4-5 hours. It is essentially inevitable after ultraendurance events like Western States, the Dirty Kanza 200, or an Ironman. Dehydration also leads to an elevated heart rate, even hours after your workout or race. When these factors combine, athletes report feeling like they are radiating heat while lying in bed listening to their heart rate in their ears.
If you have suffered through a sleepless night or a night of tossing and turning after an already-exhausting endurance event, here are some recommendations for getting more and better sleep next time:
- Maximize your fitness: As with many aspects of performance, fitness solves most problems. The more fit you are, the better you will cope with the acute stress from a workout or event. Essentially, your fitness gives you greater ability to absorb the stress before it impacts your sleep.
- Minimize lifestyle stress: “Let it go, let it go…” Seriously, the stress you’re carrying from your job or your busted car or your visiting in-laws just pours more cortisol on the fire and heightens the sensitivity to excitatory hormones like epinephrine (until a chronic overload of these hormones subsequently reduces your sensitivity to them).
- Ease up on the stimulants: Remember, caffeine doesn’t actually give you any additional energy. It primarily helps with focus and awareness, and in that regard consuming more doesn’t necessarily lead to greater benefit. In long events, caffeinated products are not likely to help you all day. A better strategy for endurance events is to consume caffeine before a portion of the race where you actually need it. Read more on caffeine for endurance athletes.
- Proactively cool down: Many athletes have gotten the message about post-workout or post-event rehydration and fuel replenishment. But proactively bringing your body temperature down is also important. Effective methods include wrapping yourself in wet towels, dousing clothing with cold water, ice packs, cool water immersion (not necessarily ice baths), cool showers, and hanging out in an air-conditioned environment.
- Cool your sleeping environment: Both core and skin temperatures decline when you fall asleep, and a cool sleeping environment helps create a temperature gradient that facilitates this process. Everyone is a bit different, but optimal room temperatures for promoting restful sleep are typically in the 60-70 degree Fahrenheit range.
CEO/Head Coach of CTS
Shahsavar, Ali Reza, and Mohammad Javad Pourvaghar. “Follow-Up Alterations of Catecholamine Hormones after an Intensive Physical Activity.” Biosci., Biotechnol. Res. Asia Biosciences Biotechnology Research Asia 8.2 (2011): 591-95. Web.