How Does Sleep Deprivation Influence Exercise?

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Cilliers Marais


Do you like to exercise, but you often find that you are too tired to work out properly?

Well, don’t feel alone in your struggle. There are millions of people (and I literally mean millions) out there that face the same problem…

Sleep deprivation.

All of us have been there one time or another. Or am I wrong? Have you never spent a sleepless night in your life? If so, please tell us what you do in the comments below! Because I can fall asleep fairly easily. But still, I get those nights where, no matter what I do, I just can’t drift off.

Anyhow, how does sleep deprivation and exercise go together? Read on to find out.

What is Sleep Deprivation?

Tired after not getting enough sleep and too much exercise?

Simply put, it is when you don’t get enough sleep. If you type in “sleep deprivation” and hit search in your browser, the answer will be something like this:

“The situation or condition of suffering from a lack of sleep.”

Google Dictionary

It can come in many forms. Sometimes, you just can’t fall asleep. Other times, you drift off quite easily, but then something wakes you up. And no matter what you do, you just can’t go back to sleep afterwards. Or maybe you suffer from obstructive sleep apnea (OSA) and you are not aware of it.

For those of you that don’t know, OSA is a condition where you stop to breathe for intervals while you sleep. Then you wake up, gasping for breath and go directly back to sleep. More often than not, you won’t even notice that you keep on waking up during the night. However, you will notice that you don’t feel well-rested at all when you wake up in the mornings. (If this is you, get it checked out).

But now, the real question is, what does this have to do with exercise?

Sleep Deprivation and Exercise

Exercise and Sleep Deprivation

When we are deprived of sleep, exercise isn’t as effective or easy as it should be. Have you ever played a competitive league game after pulling an all-nighter? I have and let me assure you, it was not pleasant! Everything just seemed to go wrong. I missed tackles, made weak passes and conceded two short corners (field hockey).

After that, I nearly lost my spot on the team because the coach was really ticked off about my performance. Needless to say, I tried my utmost to never end up in the same situation again. I tried not to mix sleep deprivation and exercise together again!

But I asked myself this: Why was my performance so bad?

And the answer was simple; I didn’t get enough sleep the night before the game.

So I went ahead and did some light reading as to why this was the case? What did the lack of sleep do to my body? Why did I perform so badly after not getting a good night’s rest?

Turns out being sleep deprived before a match, or just before exercise can have all sorts of negative effects on your performance. Check this out. Sleep deprivation can have a negative impact on all of the following:

  • Muscle recovery
  • Reaction time
  • Decision making
  • Mental focus
  • Staying motivated

Okay, so I have one example of me having a bad game after not getting in enough zzz’s. Is that enough evidence to categorically state that sleep deprivation and exercise don’t go together? Of course not! Luckily, there is a tonne of research to back up my statement.

What do the Sports Scientists Say?

What do the scientists say?

I read quite a couple of research articles on the correlation between exercise and sleep deprivation. And to be honest, there are different opinions and findings out there.

So not to be biased, I thought I’d throw in all of the opinions. Then you can make up your own mind. How does that sound? Let’s start from the oldest study and then work our way up to the more recent stuff.

Study 1 – Sleep Deprivation only affects time to exhaustion

In a 1989 article published in Sports Medicine, the researchers found that sleep deprivation only affects time to exhaustion in athletes. In other words, they said that if you do not sleep enough prior to exercise, the only negative impact that it will have on your training session is it will make you feel tired earlier on than normal.

According to this particular study, sleep deprivation didn’t have a negative impact on:

  • The strength of athletes
  • Blood flow throughout the body
  • An athlete’s breathing ability
  • Intensity at which an athlete can focus

The study concludes that being sleep deprived makes the body more resistant to insulin. So basically, if you don’t get enough sleep your body won’t be able to release as much energy as it normally does.

Study 2 – Short term sleep deprivation does not affect the power output of athletes

A 1994 research article in the Journal of Sports Sciences found that missing out on a night’s worth of sleep didn’t decrease the power output of cyclists.

So basically the study showed that, in both men and women, staying up all night didn’t rob cyclists of their strength. They could still peddle with the same intensity and power after pulling an all-nighter.

Study 3 – One sleepless night retards reaction time in athletes

In 2012, the Asian Journal of Sports Medicine published an interesting piece on sleep deprivation and reaction time.

According to these researchers, a sleepless night before intense anaerobic exercise didn’t affect the power output of athletes. However, it did negatively affect their reaction time. The study concludes that sleep plays a critical role in restoring cognitive function.

Study 4 – Short term sleep loss makes you think you are tired before you are actually tired

The American College of Sports Medicine published a study in 2013, wherein they found that sleep deprivation makes athletes think they’ve reached their limit before they actually did.

Like with study 2 above, this study was also conducted on cyclists. Twelve male cyclists were tested to see how they performed the same task on the bike after a good night’s rest and after not getting enough shut-eye. The study found (like study 3) that the athletes were slower to respond after losing out on their sleep. Another interesting thing that they found was that the athletes thought they were exhausted before their muscles were actually showing signs of exhaustion. That is something to think about…

So far, all of the studies focused on going without sleep for one single night.

And I don’t know about you, but from my point of view, it looks like even after one sleepless night, you won’t be exercising at your peak. Do you agree with me? So if that is the case, what happens if you consistently lose out on those precious zzz’s?

Well, it’s not a pretty picture!

Most of us exercise to stay fit and to live healthy balanced lives, right? Sure, some of us do it for a living, but hey! Not everyone has the talent and time to be a professional athlete (although I wish I had…).

The fact is, when you consistently lose out on sleep, you are not living a healthy life. Period.

And here is the bad part. If you don’t sleep enough AND you hit the gym every day… Double whammy! You are most likely doing more harm than good. Here’s why:

You Will Stress More

Sleep deprivation can increase stress levels.

I don’t know about you, but feeling anxious and stressed is not high up on the list of things that I like to experience. Moreover, when I don’t get enough sleep I tend to become more anxious and when I become more anxious I struggle to sleep.

It’s a bad feedback loop.

But now, if you add exercise to the mix, it doesn’t get better. Even though you think that it should…

I mean, shouldn’t exercise be a stress reliever? That is what all the blogs about stress relief say, isn’t it? Surely, there must be some truth in that?

Well yes, if you sleep enough, working out is a great stress reliever. Unfortunately, if you don’t get enough sleep training doesn’t always do the trick. Why? It’s simple, really. When we don’t get enough sleep, cortisol levels in our bloodstream is too high. And as most of you should know, too much cortisol increases our chances of being stressed.

And did you know that intense exercise also increases cortisol levels in the bloodstream? So by doing a strenuous workout after not getting enough shuteye for two weeks will most likely make you feel more anxious and stressed.

Your Chances of Injury Increase

Sleep Deprivation can cause injury during exercise

In the online journal; Sports, a very recent study found that athletes are more prone to get injured in contact sports if they do not sleep enough. In this study, researchers monitored 8 professional athletes for the six week period prior to a tournament.

They found the following in the athletes that did not have a consistent sleep pattern:

  • They had a slower reaction time than the ones who slept enough.
  • The ones that didn’t sleep enough got tired and lost focus sooner.
  • Because of fatigue and slower reaction times, they were more likely to get injured.

Another very interesting phenomenon was that athletes who didn’t have a regular sleeping pattern took longer to fall asleep than the ones who went to bed at the same time every night! Isn’t that crazy?

So in effect what this means is that, when you don’t get enough sleep, your body struggles to fall asleep. That sounds a bit counter-intuitive, doesn’t it? I mean, if you are tired you should think that falling asleep is easy. But it seems like the exact opposite is true.

Oh, and the ones that didn’t follow a set sleep plan also missed more training sessions than the other ones…

Overall Performance Goes Down as Sleep Deprivation Goes Up

Graph showing the link between sleep deprivation and performance.

In our blog post on World Class Athletes and their sleeping habits, we mentioned a couple of studies you might find fascinating.

Go check out the post and read the study that was conducted on the Major League baseball players. In short, the study found that, as the season goes on, the players make more and more mistakes.

Last year the European Journal of Sport Science published an article on elite female gymnasts. I won’t bore you with all the details, but in short, the study found that performance went down with increased training load and decreased sleep time.

The Verdict?

Clearly, constant exercise and constant sleep deprivation don’t go well together.

But luckily, you can change your sleeping habits. And let’s be honest, what better way to motivate yourself to spend more time in bed than to get a new, state of the art bed!? Especially one that is designed for athletes, by athletes, like Kooi.

Go ahead, enhance your lifestyle. Click here to shop for a bed that will make you want to go to bed every night.