A bidirectional link between sleep and physical activity: taking sleep seriously

Balancing a busy schedule, sleeping well, and working out is hard. As academics who study sleep and exercise regularly, we* spend a lot of time thinking about the best way to find a good balance between sleep and exercise. We often wonder what is the best time of day to workout? Early morning or late afternoon? Should sleep be prioritized instead of maintaining a consistent workout schedule? How do we balance a healthy sleep schedule and an active lifestyle? Interestingly, sleep and exercise are interrelated, meaning that one often influences the other. We need to sleep well to workout well, and working out may lead to better sleep. In this article, we explain the interrelation between sleep and exercise and how to choose a schedule that works best for you.

Sleep More For Better Athletic Performance

Sleep is often linked to better athletic performance. Athletes who sleep more before a competition perform better than those who sleep less¹. This poorer athletic performance may be due to reduced ability to quickly respond to new situations. For example, a football player who has slept only 6 hours may not be able to respond as quickly to a change in the game as if he slept 8 hours. In a well-rested state, the football player may be more likely to respond to unexpected situations, such as acquiring an interception. Similarly, a tennis player may be better able to return a quick serve while well-rested, compared to if she had only slept 6 hours.

Daytime sleep is also helpful for athletic performance. Athletes who nap before competition perform better than athletes who don’t sleep. Research has shown that athletes who napped for 20 minutes or less immediately before a netball game were able to jump more quickly from a squatting position than those who didn’t¹. In plain terms, napping may be helpful for quick, explosive movements, such as squat jumps.

Sleep More to Avoid Injury

Most importantly, adequate sleep is linked to reduced chances of injury¹, and getting hurt is something that we all want to avoid. Personally, we have noticed that if we still workout out, even when we have not gotten enough sleep, we often find ourselves getting hurt. For example, Erick might end up spraining his ankle during a run because he didn’t pay attention to a crevice in the sidewalk. Similarly, Emily might hurt her back during a heavy deadlift because she forgot to properly brace before a lift. These anecdotal accounts are supported by some research. For example, adolescent athletes who are chronically sleep deprived, or consistently sleep for fewer hours than needed, have a 1.7 times higher injury than those who are well-rested. Considering that injury often leads to a time of low or no exercise to allow for recovery, it’s often best to avoid any complex, high injury risk exercise when you haven’t slept well.

Stay Active to Sleep Better

Nonetheless, both exercise and sleep are important to stay healthy. The recommended amount of physical activity for adults from 18 – 65 is 30 minutes of moderate exercise (e.g., small increase in heart rate, brisk walk or jog) at least 5 times per week or 20 min of vigorous exercise (e.g., large increase in heart rate, sprinting) at least 3 times per week.

Exercise is related to better sleep quality. When you consistently engage in some sort of physical activity, you’re also more likely to sleep well. People in exercise interventions, who are given a prescribed workout schedule, often have more restorative sleep compared to those with comparatively little physical activity². Specifically, they are more likely to spend greater time periods in deep sleep stages (e.g., slow wave sleep) as compared to those who are less active.

On a continuous scale, more physical activity is often related to better sleep efficiency, or more continuous, uninterrupted sleep³. In other words, sleep continuity increased with physical activity. However, as with everything, it is important to note that excessive physical activity may not be helpful for sleep. In fact, engaging in vigorous physical activity near bedtime (e.g., ~ 1 hour) may lead to more disrupted sleep, lower quality sleep².

So When Should You Workout?

It depends. There are three key questions. You have to ask yourself, (1) Which time allows you to get enough, high quality sleep? (2) When do your daily responsibilities begin and end? (3) What kind of workout do you want to do? I’ll explain a way to work through each question below.

(1) Aim to get at least 7-8 hours of sleep each night. Avoid working out while you’re not well-rested, as this may impair your athletic ability and reduce the potential of your workout. More importantly, it may lead to injury.

(2) Make your workout time fit with your schedule. If you start working early, you may want to leave your exercise routine for later in the day to ensure that you get enough sleep. If instead, you start later in the day, your workout routine may fit earlier in your schedule and still allow for enough sleep.

(3) Be strategic about the time of day and your chosen workout. Plan your workout time based on whether you want to engage in low intensity (e.g., walking, gentle yoga) or high intensity (e.g., running, power yoga). High intensity workouts may make it more difficult to fall asleep and lead to more fragmented sleep, while lighter activities like walking and gentle yoga, or stretching, may not negatively affect your sleep quality. Anything that does not involve significantly elevated heart rate or sweating has a lesser chance of negatively impacting sleep.

Take-Home Message

Sleeping enough can help you to perform better and stay injury-free. Reciprocally, staying active may also help you sleep better. But be careful about when you workout and which ones you choose to do. Do what works for you and your schedule. Make sure that you get enough sleep before trying to workout. If you have to go to work early and don’t have time to get at least 7+ hours of sleep, workout after work. In any case, be kind to your body.

References

Notes

* This post was coauthored by Emily Hokett and Erick Keigen.

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