How Does Sleep Affect Your Exercise?

We all know that our diet has an enormous impact on how effective our exercise is. But have you ever really thought about what influencing factor your sleep has on your workout?

You surely exercise for a purpose: to be more energized, to lose weight, to increase muscle mass, and much more. You drag yourself into the gym, go running in even extreme weather conditions, completely exhaust yourself in boot camp classes and on top of that, you do everything to avoid too much sugar or fat.

But despite all these efforts, you are feeling that you don’t get the expected results. If that sounds familiar to you, here is what might be interesting for you: all of your workout goals may be doomed to failure if you don’t get enough sleep. In other words, it strongly depends on the quality and length or your sleep, if your workout will deliver the expected benefits.

How does sleep help your exercise routine?

Sleep and exercise are strongly correlated. If you do not get enough sleep, you will hardly be able to perform well when exercising. Also, in case you started a new workout routine to lose some weight, lack of sleep will ensure that this goal will not be achieved. While continuing with your exercise, you might even keep on gaining weight.

Having an adequate sleep on the other side will result in more productive exercise, which then again helps to improve your overall sleep quality. One of the main reasons for this correlation between sleep and exercise is, that exercise helps to increase insulin sensitivity and decreases body fat.

Too much body fat is one major cause for obstructive sleep apnea (OSA), a serious sleep disorder in which breathing is repeatedly interrupted and which leads to poor quality sleep. What many see as a vicious cycle of bad sleep -> sleep disorder -> weight gain and even poorer sleep, can be turned into a positive cycle by physical activity: workout + good sleep -> curing sleep disorder -> better sleep + better workout performance.

The relationship between sleep and learning

There is another important factor why the quality of your sleep can have a profound impact on the performance of your workout. Sleep is the time when your brain processes new learnings and memories from the day, whereas lack of sleep impairs your ability to focus and learn efficiently.

Let’s say for example you just started to learn how to play tennis. There are quite a few techniques you need to practice in order to master even a simple ball exchange. Also, your improvement will heavily depend on your agility and ability to react fast.

This is where sleep comes into play because that’s when your brain processes all that you have learned during your training sessions and make it stick so that you can recall it in the future. If you are sleep-deprived, your performance will most likely be poorer than with an appropriate amount of sleep. Your reaction time will be slower, and it will take longer for you to master the technical and strategic challenges of the new sport.

How does the positive correlation between sleep and exercise work exactly?

During sleep your body produces growth hormones, also called the human growth hormone (HGH or hGH). The growth hormone is essential for repairing and restoring your muscles, bones, and tissue from the strains of the day. Many people think that the growth hormone is produced only during childhood and adolescence. While it is immensely important in your early life because the growth hormone stimulates your bone growth and makes you grow, your body actually never stops producing it. In fact, the growth hormone keeps its vital function for a healthy metabolism and good physical performance until you are dying.

So when we are saying that it is during sleep when your body recharges and conserves energy, what we are really referring to is that sleep gives our body the opportunity to produce enough growth hormones. If you are sleep-deprived, your body will struggle with this critical task, and you will not be able to recover from the stress of the day, or building up the muscles worked during exercise.

How does exercise influence your sleep?

If sleep and exercise go hand in hand, then the next question is how does exercise effects your sleep? If you workout on a regular basis, it will help you to fall asleep faster and to stay asleep, both combined leading to better quality and more regularity in your sleep. Not only that you will feel much more relaxed and stress resistant during the day, but you will experience more energy, the basis for increased performance during a workout.

Usually, the more intense your training is, the more tired you typically feel after the exercise. You probably have experienced it yourself that after a long hike in the wilderness or an extended mountain bike trip you are so exhausted that you barely could crawl into bed. In those cases, your body needs instant rest to fuel up its energy levels which were used up during the intense exercise.

But keep in mind that in order to improve your overall sleep quality, a sporadic high-intense physical activity will not do the trick. In fact, if you push yourself too hard, it can have adverse effects. You might experience more prolonged periods of extreme tiredness, also known as fatigue; or the exact opposite, meaning you end up lying awake in bed tossing and turning despite being thoroughly exhausted.

Why is that? How can an exhausting activity lead to two exact opposite states, fatigue and sleeplessness? Let’s look at what actually happens during exercise in your body: For your body to keep on moving it gets the energy from a molecule called Adenosine triphosphate (ATP). ATPs are used as the primary energy source for metabolic functions in your body. As long as you stay at a moderate intensity level with your exercise, your body manages to recover effectively. However, if you engage yourself in strenuous activities, the demand for ATP is higher, and it leaves your energy reserves depleted which causes extreme exhaustion and fatigue.

How can an exhausting event leave you sleepless?

Now let’s look at the opposite effect, that extreme exhaustion can leave you sleepless, also know as post-exercise insomnia. Several factors can contribute to the inability to fall asleep or stay asleep after an intense workout, but the two hormones cortisol and norepinephrine are playing a significant role in post-workout sleep disorder.

Why is that? Any kind of exercise increases your heart rate and helps pump more blood through your system, which is also what raises your core temperature. In addition, physical activity stimulates your nervous and endocrine system which leaves you in an excited or aroused state. The more intense the exercise is, the longer you are in this excited or aroused state.

Responsible for this condition is primarily the stress hormone cortisol, which your body releases during exercise. What sounds alarming is actually a natural and healthy way for your body to adapt to the increased physical strain, or in other words stress, which occurs during a workout. However, if your training workload is too strenuous and your body cannot recover adequately from the exercises, the cortisol levels in your body might be chronically elevated. As a result, you in are in a continuously excited state which is not very beneficial when trying to sleep.

Same with adrenaline and norepinephrine; the level of these two hormones also increase whenever you find yourself in an excited state. Adrenaline levels fall quickly after exercise, but norepinephrine levels can stay elevated for up to 2 days after an exhaustive training and might additionally contribute to your struggle to fall or stay asleep.

Will moderate exercise help you to sleep better?

Yes, research has shown that moderate-intensity workouts (like swimming, walking, riding a bicycle or carrying out indoor cycling at a moderate pace) have a very positive impact on your sleep and on your overall quality of life. Exercising also helps to maintain your circadian rhythm (your body’s internal clock) because when being physically active your body knows that the schedule is on.

And it gets even better: these positive effects were also found with people who are suffering from chronic insomnia. Apparently, the right workout can often contribute more to a good night’s sleep than sleeping pills!

In addition, moderate physical exercise in combination with the right sleep schedule is also effective in treating mood and anxiety disorders, which are often associated with insomnia. While other behavioral/cognitive treatments might be more effective, you should keep in mind that both, sleep and exercise are a healthy, safe, inexpensive, and more natural treatment resource which is less difficult and costly to deliver.

Is napping after workout beneficial?

There is no definite yes or no to this question as it depends mainly on two factors: what time of the day you are exercising and what level of intensity the workout regimen has.

In order to maintain or develop a healthy sleep routine, your main focus should be to achieve an uninterrupted 7 to 8-hour sleep with 4 to 5 sleep cycles, each reaching deep sleep stage. If you are napping after an evening exercise, the risk increases that your night’s sleep will be interrupted and hence too short. As a general rule, avoid any napping after 5 pm.

That said, in case you were doing some extremely exhausting exercise earlier during the day, a short nap won’t jeopardize your regular sleep routine; it will even be beneficial for the recovery process. The reason is that intense training often requires you to extend your total sleep time and there is no reason why you cannot do so by napping for about 20 to 30 minutes right after the activity.

However, if you regularly push it to the extreme leaving you so tired that you want to cry or die, you probably need to re-evaluate your workout plan and slow down a bit. Otherwise, you might sabotage your own fitness goals and even risk to develop a sleep disorder such as post-workout insomnia.

Should you exercise if you are feeling tired?

Provided you are not feeling sick or sleep-deprived, you should get moving. Everyone knows the moment when you get home after work feeling snoozy and exercise is the last thing on your mind. However, once you get going, you will immediately feel more energized, and this feeling will even last for several hours after the workout.

On the long run, frequent exercise will help you to boost your overall energy level, and you will feel less and less tired. Keep in mind that it doesn’t need to be any extreme training; just a 20-minute run or walk is highly beneficial when done regularly.

To prevent tiredness try to keep up your energy throughout the day. Make sure to eat regular and healthy meals and to drink enough water. Another energy-killer is stress. Start to introduce relaxing activities into your day which can also easily be carried out at work (like breathing exercises, short meditation, or simple stretching exercises).

If your stress is caused by worries talking about it is often the best way to get rid of the pressure. Address the issue to your partner or boss, ask a friend or colleague for help. We tend to forget that asking for help is often the easiest and fastest way to solve a problem and hence reduce stress.

What happens if you work out on no sleep?

A long-haul trip, an endless barbecue night, or an extended stargazing date with your loved one – there are plenty of reasons for skipping a whole night’s sleep from time to time. After all, there are only 24 hours in a day.

But if you ever have tried to work out after a night with no sleep, you may know how important sleep is for your physical performance. Not only the usual exercise, but anything active feels like an excessive strain on your body. This is no surprise. Remember, one of the primary functions of sleep is to conserve energy. People who try to exercise on no sleep usually fatigue much sooner and have to exert more energy to complete the same workout they normally do on a full night of sleep.

Not surprisingly, your physical performance is much poorer, and your staying power is strongly impaired. You just will give up when you would otherwise be physically capable of going on. The reason is that your muscles will tire more quickly. Any physical activity is fueled by glycogen, which is basically energy stored in your muscles. The more intense your training is, the more of the stored glycone is used up which leaves you feeling fatigued.

However, if you exercise on no sleep, your muscles will grow tired even before the glycogen level runs low. This is an ancient safety mechanism of your body not to run completely out of glycogen. If this happens only occasionally, there’s nothing to worry about. But if you make it a habit to work out after not getting any sleep, the adverse effects will begin to multiply and can lead to more serious health issues.

Therefore, better take it easy after an all-nighter (or only a few hours of shut-eye). Instead of dragging yourself into the gym engage yourself in passive activities such as listening to music, watching Netflix, or reading a book, or just catch up with your sleep. Your body surely needs some time to repair after a night out in town.

Is the right timing of the exercise crucial?

There is no wrong timing for your workout; you can basically exercise at any time of the day depending on how stimulating the workout is. Important is to find out what works for you. Therefore, in case you want to carry out your main exercise activities in the evening or at night, choosing the right type of workout and finding the right workout schedule is crucial.

While there are people who can calm down extremely fast even after a long endurance training, you are probably better off sticking to low to moderate-intensity workouts like yoga, pilates, or a short run. Even better is, if you are able to finish exercising 2-3 hours before bedtime. It is crucial for your body to calm down for you to be able to fall asleep.

If you are already going to the gym every night and are wondering why you have problems to fall asleep, this might be the exact reason: your cortisol levels are up, your nervous system is turned on, and you are feeling energized, which is the exact opposite of what you need to fall asleep. Therefore, it is crucial that you allow your body to relax appropriately before bedtime. Listen to your body and structure your sleep/exercise plan accordingly. This will ensure that you can maximize your benefits from the positive correlation between sleep and exercise.

Enough sleep or regular exercise – which is more important?

Enough sleep and regular exercise are both important, so does any of the two takes priority? Not really because to maintain a healthy metabolism, you need both.

That said, in times when you are not able to find the perfect balance you should prioritize your sleep. Let’s say you had a tough week and weren’t able to sleep for more than six hours most of the nights. While this is not a recommended scenario, we all are having weeks like this from time to time.

On Sunday morning you wake up still feeling tired and ask yourself if it’s better to stick to your workout schedule, get up and go to the gym, or to get some extra sleep. In that case, you are probably better off to go back to bed and catch up with your sleep. Sleep is as vital as eating for you; and especially when you are going through periods where your sleep routine gets turned upside down, it is essential to make your sleep hygiene the first priority not to risk long-term negative consequences.

At the end of the day, if you don’t get seven to eight hours of quality sleep per night, you may want to rethink your schedule which also includes your workout plan. Once you can make sure that your schedule allows you to get the required amount of sleep, you can then figure out how to fit in your regular workouts. Both sleep and exercise are absolutely necessary for you to feel great and perform well every day.