According to the American Academy of Sleep Medicine, “sleep is a biological necessity.” In a position statement, the professional organization concluded that everyone would benefit from greater emphasis on sleep in health education and clinical practice.

Why sleep is so important is not exactly clear. The process of sleep and why we do it remains mysterious in many ways. What experts know, however, is that adequate sleep makes you healthier and happier, while inadequate sleep increases the risk of serious health problems.

What Exactly Is Sleep?

We know we need it. We all do it, but what is sleep? What happens when you drift off at night? Science is still working to uncover exactly what happens when you sleep, but we do know some things about it.

Sleep Stages

Sleep occurs in stages. You should go through a few cycles of all the stages each night. All stages are important, not just deep sleep.

• During stage 1 of sleep, breathing and heart rate slow, muscles relax, and brain waves slow.
• In stage 2, all of the above continue to relax and slow even more as you begin to sleep more deeply. There are some bursts of brain activity during this time.
• Stage 3 is deep sleep. This is when your breathing, heart rate, and brain waves are at their slowest. It’s most difficult to awaken during this stage.
• REM sleep is rapid eye movement sleep, and you enter it about 90 minutes after falling asleep. Your eyes move rapidly as your breathing, heart rate, and brain waves rev up again to levels similar to wakefulness. This is when most dreaming occurs. Your muscles become paralyzed to prevent you from activity during dreams, which could be dangerous.

Why Do We Sleep?

This is still a mystery, although there are plenty of clues based on what happens when you don’t get enough sleep. From an evolutionary perspective, sleeping is risky. Being unconscious makes you vulnerable to danger. So why do we do it?

Some research suggests that sleep is a time of brain maintenance when it clears out toxins. Sleep is also likely an important time for restoring the entire body.

Another reason might have to do with brain plasticity, the ability of the brain to change and adapt. Sleep might be when the brain makes changes, organizes information, and consolidates memories. The fact that babies and children with developing brains need so much sleep supports this theory.

Top Reasons Why Sleep is Important

While the exact reasons for sleep remain mysterious, what is absolutely clear is that we need it. Sleep is important for both mental and physical health. These are just some of the biggest reasons everyone should focus on getting adequate, quality sleep.

Sleep Improves Cognitive Function

Cognitive function is the ability to think, organize, remember, and more. How your brain functions depends strongly on sleep. Sleep is linked to the processing of memories, concentration and focus, decision-making, and performance on cognitive tasks, including in school or at work.

Sleep Manages Stress

If you’ve ever felt the consequences of too little sleep, you know that stress and sleep are related. The more high-quality sleep you get, the lower your cortisol levels should be. Cortisol is a hormone the body releases when you feel stressed.

Cortisol is important. It prepares the body to act in dangerous situations. Too much cortisol, on the other hand, is a sign of chronic stress. Cortisol levels should drop at night as you prepare to sleep. If you don’t sleep, levels remain high. This interferes with the production of melatonin, which makes you sleepy.

Stress and sleep have a cyclical relationship. When you don’t get enough sleep, you feel more stress. When you feel stressed, it’s harder to sleep.

Sleep Regulates Mood and Emotions

Stress is just one aspect of mental health impacted by sleep. Mood disorders, like depression and anxiety, are also connected to sleep. The reason might be that sleep is important for emotional regulation and processing.

During the day, you have all kinds of experiences that impact your mood and feelings. Sleep might act like a processing time, helping you manage emotions. Some experts believe dreams play a role in this.

Sleep Keeps You Physically Healthy

While much of the focus on the purpose of sleep involves the brain, it is also essential for the body and for physical health. Sleep promotes good functioning of the immune system, for instance, lowering the frequency and duration of infections.

Sleep is also important in maintaining a healthy weight. Leptin and ghrelin, hormones that suppress and trigger hunger, are kept in check by good sleep. When you sleep enough, the body produces adequate leptin, but ghrelin goes up, making you feel hungrier.

There is also some evidence that adequate sleep reduces inflammation in the body. Systemic inflammation increases the risk of obesity, diabetes, cardiovascular disease, arthritis, allergies, asthma, and chronic obstructive pulmonary disease.

Sleep Helps You Be More Active

Physical activity and exercise are essential for good health, and research suggests that sleep supports them. Studies show that elite athletes need more sleep and that they perform better when they get adequate sleep.

Most people are not athletes, but clearly, sleep has an impact on energy levels and the ability to be active. To be able to get in a workout most days of the week, sleep is important.

What Are the Consequences of Sleep Deprivation?

Much of what experts know about the importance of sleep comes unfortunately from studies of all the bad things that happen to people under sleep deprivation. If you consider what happens to the brain and body when you don’t get enough sleep, it is easier to understand why it is so important.

Sleep deprivation simply means not getting the recommended amount of sleep. An occasional period of sleep deprivation is not terrible, but over time, it can lead to sleep deficiencies and significant health problems.

Accidents

Lack of sleep make you sleepy during the day. It seems obvious, but many people fail to realize how dangerous daytime sleepiness can be. If you expect to function normally during the day on too little sleep, you can cause a serious accident. In a vehicle, this can be life-threatening.

Poor Performance

Daytime sleepiness also affects how you perform at work, at school, or in other activities. Poor sleep makes it difficult to remember things, to think clearly, to problem-solve, and to remain alert and focused.

The longer you go without good sleep, the worse the effect on your cognition and performance. In fact, it can even increase your risk of developing a degenerative brain disease, like Alzheimer's.

Moodiness and Poor Mental Health

It’s difficult to regulate your emotions and find a stable mood when sleep-deprived. You likely feel grouchy, stressed, tired, and irritable. You’re less likely to make healthy decisions, which might be why sleep loss correlates with increased alcohol use.

Poor sleep puts you at a greater risk for mood disorders like depression and anxiety disorders. If you have a mood disorder, lack of sleep can worsen symptoms or bring on new episodes of symptoms.

Damaged Relationships

Relationship stress is a common consequence of poor sleep. Without enough sleep, you can be moody and stressed, which can bring you into conflict with others. Poor sleep actually lowers your emotional intelligence, making it more difficult to interact socially.

Long-Term Health Problems

Chronic sleep deprivation increases the risk of many health issues, including heart disease, stroke, obesity, high blood pressure, diabetes, infections, and more. Poor sleep can directly impact these problems, but it also has an indirect effect on health.

When sleep-deprived, you are less likely to make healthy lifestyle choices, to eat well or exercise enough. It’s easier when tired to skip a workout and reach for unhealthy snacks. You might also drink more alcohol to relax or use drugs to stay alert.

Reduced Quality of Life

All of these factors come together to reduce your quality of life if you don’t sleep well or enough. Worse health, moodiness, stress, weight gain, poor performance, relationship struggles, and all the other negative consequences of limited sleep come together to make you less happy and satisfied with life.

How Much Sleep is Enough Sleep?

Everyone is different when it comes to sleep. Some people need more, and others do just fine with less. However, there are some general guidelines that most people should follow:

• Most adults need between 7 and 9 hours of sleep per night.
• As you age, you are likely to sleep less at night and to sleep more lightly.
• Babies, with their rapidly developing brains, need to sleep 16 to 18 hours per day.
• Toddlers and young children should sleep between 10 and 13 hours a day.
• Older children and teens should sleep about 9.5 hours each night.
• Catching up on sleep on the weekends is not a good strategy for getting adequate sleep. Sleep should occur on a consistent schedule.

How to Fall Asleep Faster and Stay Asleep Longer

The importance of sleep is as much about what sleep does for your health as the negative consequences of not getting sleep. Do more than simply get enough sleep. Prioritize it and try to improve the quality of sleep you get. Instead of just getting by, embrace sleep as one of the non-negotiable factors in good health.

Sleep deficiency is more than just not getting enough sleep. It includes sleeping at times that aren’t ideal; for instance, if you have a third-shift job. It also includes poor quality sleep or living with a sleep disorder, like insomnia. Anything you can do to sleep better and longer will reduce your deficiencies and improve your health and quality of life.

Maintain a Regular Sleep Schedule

One of the most effective ways to sleep better and combat sleep disorders is to be consistent. Go to bed and wake up at the same time every single day to the extent that you can. Don’t shift for the weekend. This is a common mistake, but it is detrimental to regular sleep.

Exercise and Spend Time Outside Daily

Exercise is also extremely effective for improving sleep. Exercise helps combat mood disorder symptoms and stress. It can also tire you out in preparation for bed but avoid too much activity in the evening. If you can do it outside, it’s even better. Exposure to sunlight supports a normal circadian rhythm so that you naturally get sleepy when it gets dark outside.

Create a Soothing Bedtime Routine

As part of a regular sleep and wake schedule, create a routine that prepares your mind and body to relax into sleep. Make these relaxing steps a habit, and your brain will start to recognize bedtime and begin to get sleepy. Try meditation, a bedtime story, reading, or a warm bath as part of your nighttime routine.

Avoid Food, Drink, and Screens Before Bed

In the couple of hours before bed, avoid eating too much. If you’re hungry, have a light snack. The process of digesting food, especially a heavy meal, disrupts sleep. Alcohol also disrupts sleep, even if it makes you feel tired initially.

Put your screens down at bedtime and either listen to soothing stories and music on the BetterSleep app or use a guided meditation. Reading emails or scrolling through social media are counterproductive to sleep.

See Your Doctor if Necessary

If you try steps like these to prioritize sleep but still struggle to get a good night's sleep, you might have a sleep disorder. You could also have another medical condition causing insomnia. See your doctor to get a diagnosis, to rule out any underlying conditions, and for a referral to a sleep or mental health professional.

Getting more sleep, and quality sleep, as many nights as you can is so important for your health and well-being. It’s worth prioritizing as much as you do other health decisions, like eating right and exercising. Understanding the necessity of sleep is the first step in making positive changes.