last updated May 26, 2021

Why Sleep Is Important and How to Sleep Better

by Rob Arthur

Contrary to what you may have heard, sleep isn’t for when you’re dead.

In this article, we’ll talk about what sleep is, why it’s important, its benefits, and how to sleep better.

If you have any questions at the end, let me know in the comments 🙂

What is sleep?

Sleep is not just some passive absence of wakefulness to allow for rest.  

It’s a highly organized, active process that follows a regular, cyclical pattern that involves changes to our body’s organs (1).

Sleep is typically organized into two main stages (2):

  • Non-rapid eye movement (NREM)
  • Rapid-eye movement (REM)

The NREM stage comprises four additional substages – N1, N2, N3, and N4.

Each NREM and REM stage represents a different pattern of brain activity, blood pressure, body temperature, heart rate, breathing, hormone secretion, and muscle tone.

We’re still learning what actually happens during sleep, but so far we’ve seen its purpose extend beyond any one specific function.

Why is sleep important?

Sleep is essential for development, energy conservation, brain waste clearance, immune response, cognition, performance, and disease (3).

There’s quite a bit of research demonstrating its connection to a variety of health outcomes.

Associations with disease

Poor sleep has been linked to dysregulated immune response (4), non-alcoholic fatty liver disease (5), and systemic inflammation (6).

It’s also a risk factor for cognitive decline and dementia, including Alzheimer’s (7), as well as mood disorders (8).

One large meta-analysis of over 5 million people found short sleep duration to be linked to diabetes, hypertension, cardiovascular diseases, coronary heart diseases, and obesity (9).

That said, the studies above are observational, meaning they’re looking for patterns in populations.

They aren’t designed to demonstrate which observations are causes and which are effects.

For example, there is strong evidence for sleep disturbances having a bidirectional relationship with depression (10).

That is, they’re often an effect of depression, rather than a cause.

We see a similar relationship between sleep and anxiety, obsessive-compulsive disorder, and post-traumatic stress disorder (11).

Furthermore, a large meta-analysis similar to the one previously mentioned found long sleep duration to be linked to similar negative health outcomes (12).

Yet, when we look at interventional studies where sleep is deliberately extended, we see primarily benefits.

Let’s take a look at some of those studies to get a better feel for the effects of sleep on health.

We’ll start with your efforts to get leaner, bigger, or stronger.

Body composition

A 2018 study showed that participants who restricted calories and reduced their sleep by an hour a night lost less fat and more muscle than those who slept as they normally would (13).

In a 2020 study, weight loss participants who extended their sleep by an hour and a half experienced greater weight loss, reduced waist circumference, and lower insulin levels than those who extended sleep by only a half an hour (14).

Inadequate sleep can also impair muscle growth and strength gains (15,16).

These effects on body composition are reflected in other markers of metabolic health.

Metabolic health

Along with weight gain and loss of lean mass, poor sleep can promote increased appetite and caloric intake, reduced insulin sensitivity,  impaired glucose control, and cortisol dysregulation (17).

Experiments in which sleep is extended, however, have resulted in improved insulin sensitivity, leptin profiles, appetite, desire for sweet and salty foods, sugar intake, and protein intake (18).

In addition to body composition and metabolic health, we can see effects on athletic performance as well.

Exercise and athletic performance

Sleep restriction and deprivation have been shown to negatively affect both the mental and physical aspects of exercise and sports performance and recovery (19). 

As you might have already guessed, sleep extension appears to have the opposite effects (20).

Sleep doesn’t only affect your physical health, which we’ve been focused on so far.

It also impacts your ability to think clearly and perform mentally.


Neuroimaging studies show sleep deprivation to impair attention, focus, working memory, risk/reward processing, impulsivity, emotional processing, and learning (21).

Correcting sleep deprivation, on the other hand, can improve cognitive function, attention, memory, and executive function (22).

All of this suggests that while longer sleep can be a sign of disease, it’s not likely it’s a driver of disease.

Short sleep, on the other hand, doesn’t appear to offer much benefit in any situation.

Now we’ll discuss what you can do to help your sleep habits work for you, not against you.

How to sleep better

There are steps you can take before bed – often referred to as “sleep hygiene” – to prepare your body for a restful night.

Sleep hygiene

Set a bedtime that allows for 7 hours of sleep, establish a relaxing bedtime routine, keep your bedroom quiet, comfortable, and cool, and use your bed only for sleep and sex (23).

You might also aim to get regular exercise, manage stress, reduce noise, set a consistent bedtime, and avoid caffeine, nicotine, alcohol, and daytime napping (24).

Light exposure is another factor to which you might want to pay attention.

Get plenty of bright light early and throughout the day, while minimizing bright light – especially from artificial lighting, smartphones, and screens – at night (25).

If you must use screens at night, consider wearing amber-colored blue light blocking glasses for 2 hours before heading to bed (26).

You may also want to pay attention to your eating habits.

Make sure you’re eating enough, particularly protein and carbohydrates, and consider supplementing with melatonin, GABA, or glycine (27,28).

If none of this works, consider if other health issues are at the root of the problem.

Underlying health issues

We mentioned earlier that sometimes sleep issues are symptoms, rather than drivers, of disease.

If you’re having trouble sleeping or are sleeping for longer than normal, you might also consider other aspects of health you might want to address.

Eat well, enjoy physical activity, manage stress, and spend time with people you love.

Reach out to a physician or other professional when necessary.

We all need help sometimes, and there’s no shame in that.

Let’s wrap this thing up with some tips on how to start putting all this into practice.

What to do now

You don’t have to take all of these steps at once.

As a matter of fact, you might find taking one at a time to be more effective.

Such an approach might help you better identify which steps help and which ones don’t.

After all, different strategies work and don’t work for different people.

Ideally, you’ll start with something that seems easy and manageable.

Then, pay attention to any changes you observe.

Do you fall asleep faster or stay asleep longer?

Are you waking up feeling more refreshed?

Do you have more energy?

Is your mood improving?

Are you more focused and alert?

Has your training progress improved?

If you find a specific strategy helpful, keep it up.

If not, let it go.

Find what works for you.

This may take time.

This may take effort.

It will be worth it.

You’re worth it.

You’ve got this.


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