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How Sleep Affects Your Fitness and Weight Loss

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Quick question: which areas do you think you need to focus on most when you are trying to get fitter and lose weight?

Like most people, you most probably said diet and exercise. And you are absolutely correct.

But there is one other factor that we tend to neglect when it comes to staying fit. That is sleep, specifically quality sleep.

For centuries scientists have been trying to figure out exactly why we sleep. There are a lot of theories but we still don’t really know why every evening we pass out for several hours.

But over time, researchers have found that sleep is strongly correlated to various effects on our mental and physical health. They have discovered that sleep improves memory, makes us happier and boosts productivity.

They have also discovered a strong link between sleep and fitness.

The cause-and-effect is actually quite simple. Good quality sleep results in better fitness and more effective weight loss. Poor sleep habits increase the risk of obesity and make it harder to get fit.

The fine details are of course a bit more complicated than that. And that’s what I want to discuss in this post.

Specifically, I’ll explain 5 ways sleep affects your fitness and weight loss efforts. All of them backed by science.

If you are currently on a fitness or weight loss journey, you'll hopefully understand why you should start ranking quality sleep right there at the top of your priorities along with diet and exercise.

1. Sleep Affects Your Appetite

You get hungrier when you sleep less

Your appetite is controlled by two key hormones. They are called the ‘hunger hormones’.

One of them is ghrelin. This hormone sends hunger signals to the brain, which then prompts you to eat something.

The other is leptin. This hormone suppresses appetite. In other words, it tells your brain that there’s enough food in the body which prompts you to stop eating (at least, that’s how it’s supposed to work – many people tend to ignore it, leading to overeating).

When you sleep well for the recommended 7-8 hours, these hormones function normally. However, when you are sleep deprived, levels of the ghrelin hormone go up even if you are full.

This makes you feel hungry and more likely to take in more calories.

So if you find yourself hungry after a particularly short night, don’t wonder why.

2. Sleep Affects Your Energy Levels

While we don’t fully know why we sleep, we know that it is essential for keeping our bodies energetic.

Sleep provides the body with an opportunity to refill its energy levels before the next day.

If you don’t sleep well, you won’t have the energy to hit the gym or track the next morning. Even if you force yourself to go running or do some weight lifting, you’ll find that your workout is not as effective as usual.

You’ll find yourself running slower, lifting fewer reps and getting tired more quickly.

Even sleeping an hour or couple of hours less than the recommended amount will have a significant effect on your energy levels.

The worst thing is that it carries over for several days. If you get only 4 hours of sleep on Sunday night, you’ll be feeling off kilter the rest of the week even if you make an effort to sleep well the other days.

3. Sleep Affects Your Metabolism

If you look at the sleep duration of different animals, you’ll notice an interesting pattern.

Large animals sleep for fewer hours (an elephant sleeps for 2-3 hours) while smaller animals spend most of their day asleep (rats can spend 18 hours a day snoozing).

Scientists think this has something to do with metabolism. Small animals have higher metabolic rates and hence need more sleep.

Altering your sleep duration from the normal amount can have drastic effects on your metabolism. In one study, participants who slept for only 4 hours a night for 6 nights had their metabolic rate drop by 40%.

A lower metabolic rate means more fat gets stored in your body (rather than being burnt for energy). Obviously, that will make it more difficult to lose weight and get fit.

4. Sleep Affects Your Decision Making Capability

Poor sleep often leads to poor dietary decision making

Poor sleep quality can impair your decision making process, making you more likely to make bad decisions when it comes to food choices.

Several studies have shown that people who sleep for fewer hours tend to eat more junk food even when healthy food is easily accessible.

When you combine the increased levels of ghrelin with diminished willpower, you can see why you are always so tempted to get a high-sugar breakfast after a poor night's rest.

5. Exercise and Sleep are Interlinked

Exercise and sleep have a circular relationship.

If you sleep well, your workouts will be more productive. When you work out, you sleep better.

That’s why it is important to exercise even when you are not feeling up to it. Even a few minutes of intensive exercise can help you sleep better at night which in turn helps with your fitness and weight loss.

Improving Your Sleep Quality

The first step to improving your sleep quality is to figure out why you are not sleeping well and deal with it.

If you are using electronic gadgets at night, shut them down an hour or two before sleep and keep them away from the bedroom.

If you are feeling anxious or stressed, then use relaxation techniques such as meditation and yoga. If needed, check yourself into one of those week-long yoga retreats to learn these skills.

Also make sure you have an optimal sleeping environment. The temperature should be slightly lower than usual (ideally less than 70 degrees F), your bedroom should be dark and there should be no disturbing noises.

Your mattress should also feel cool and comfortable.

If you suspect your mattress is the reason you can’t sleep well, then use our mattress mattress buying guides and comparisons to find a comfortable mattress online.

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