The Importance of Sleep: An Ultimate Guide to Sleep and Health

importance of sleep

Table of Contents
Why is Sleep Important?
Phases of Sleep
Sleep and Obesity
Sleep and Heart Health
Sleep and the Immune System
Link to Mental Health
Sleep’s Impact on Accident Risk
How Much Sleep is Needed?
Optimizing Sleep Space
Addressing Sleep Apnea
Sleep and Travel
Diet and Sleep
Other Sleep Tips

Is it possible to overestimate the importance of sleep? Sleep plays a critical role in both physical and mental health. A lack of quality sleep can have a serious impact on the immune system, brain function, and mood. Plus, how we choose to live our life impacts our quality of sleep. We have seen financial debt’s effect on sleep and the adverse effects on college students who are not getting enough sleep.

Conditions associated with sleep problems include depression, Alzheimer’s, obesity, and more.

This guide aims to provide an overview of these health conditions, their connections to sleep, and how to improve overall well-being with healthy sleep.

Sleep isn’t optional; it’s necessary. We spend a surprising amount of time asleep. According to the Division of Sleep Medicine at Harvard Medical School, we spend an average of a third of our lives asleep.

guide to health and the importance of sleep

Why is sleep so important? And what happens to your body when you don’t get enough sleep? These are just a few of the key questions we will answer.

Looking for a new mattress to help you sleep better? Refer to our Best Mattress Reviews of 2019 to see our recommended choices.

Why is Sleep Important?

While everyone feels a deep and compelling need to sleep, scientists have long wondered what sleep does for us. There are various theories on why we sleep, such as the evolutionary theory of sleep, and the repair and restoration theory of sleep. To better understand the value of sleep, researchers kept humans and animals awake for long periods of time, measuring what happened to their bodies and their behaviors when they didn’t get enough shut-eye.

But, a body unable to sleep is a body undergoing stress. Stress, no matter the cause, can be deeply damaging to body and mind. So, interpreting what changes are caused by stress and what changes are caused by sleep can be difficult to untangle.

While scientists have a lot of work to do to uncover what happens at a cellular level as we rest, some overarching themes about the benefits of sleep have become clear.

It seems most tissue repair and muscle growth happens while we are sleeping. While we rest and relax, the cells in our bones and muscles are fixing the damage that occurred during the day. The cells are splitting, growing, and changing, making similar tissues to replace the issues that cannot be fixed. Without sleep, this couldn’t happen.

Plus, researchers discovered sleep deprivation could lead to damaged cells. Rats were subjected to no sleep or 35% less sleep for 10 days and then allowed to sleep for two days. Among the rats with no sleep, researchers found tissue damage in their:

  • Liver
  • Lung
  • Small intestine

Overall, the sleep-deprived rates had 139% more DNA damage than the rats with smaller amounts of sleep deprivation.

Cells replicate by copying DNA. When the rats didn’t have enough sleep, they made copying errors. They also had difficulties with energy production. Put together, this means rats with no sleep were at risk for many different kinds of health issues.

The brain also relies on sleep. In 2013, researchers uncovered a sort of “cleaning state” that happens within the brain during sleep. As the researchers told National Public Radio (NPR), they discovered the brain shrinks during sleep, allowing cerebrospinal fluid to move in and out of the brain very quickly, which helps wash out toxins.

sleep research study data

The substances washed away are natural brain waste products, but those substances are toxic to healthy brain cells. Washing them away keeps the brain healthy and active.

These benefits don’t take hold as soon as your head hits the pillow. To really reap the benefits of sleep, you must move through a very controlled process known as a sleep cycle.

The Importance of the Sleep Cycle

Our bodies move through different types of sleep throughout the night, broken down into stages. Researchers have known about these sleep stages since the 1930s.

But the science of sleep is fluid. At the moment, there are four approved sleep stages, described as:

  • Stage N1: We begin to drift off, and we fall into a very light sleep.
  • Stage N2: Breathing and heart rates become regular, body temperature drops; we disengage from the world around us.
  • Stage N3: We fall into a deep, restorative sleep. Blood pressure drops, muscles relax, hormones are released, and tissue-repair processes take hold.
  • REM sleep: The brain is active, and the eyes dart back and forth. We are unable to move our muscles.

finding the best solutions to a better night's sleep

Throughout the night, we move into and out of these stages of sleep. But if we spend more time in the early stages of sleep, we can awaken just as tired as we were when we fell asleep.

Both the quantity and the quality of sleep matters. We need to ensure the rest we get is truly restorative. While sleeping in may feel great, too lax of a sleep schedule can indicate an unhealthy sleep cycle.

What happens when we don’t get the sleep we need? Let’s discuss the consequences in detail.

Sleep and Obesity

When we talk about weight-control strategies, we often focus on the foods we eat and the exercises we perform. Sleep also plays a big role in your weight. In fact, the number of hours you sleep could relate directly to the number of pounds you see on the scale.

In 2013, researchers writing for the journal Current Opinion in Clinical Nutrition and Metabolic Care reported sleep deficiencies could change your metabolism and impact your endocrine system.

Researchers say sleep loss can change the way your body deals with digesting sugars. Typically, the pancreas releases just the right amount of insulin to help your body process the sugars you eat. Lack of sleep can make your body more sensitive to the presence of glucose, and it can make your body less sensitive to insulin. So, your pancreas might be required to make twice as much insulin to help you process sugar. At the same time, as your quality of sleep decreases, your appetite may increase.

how the sleep and body cycle work

A pancreas under pressure can stop producing insulin. When that happens, you may qualify for a diagnosis of diabetes, and you may require regular insulin shots. Even if that doesn’t happen, the metabolic changes caused by a lack of sleep can cause you to put on weight, another risk factor for diabetes.

Sleep can also cause persistent lifestyle changes that could add up to weight gain. For example, researchers writing for the T.H. Chan School of Public Health at Harvard report that sleep deprivation gives you more time to eat. Those extra calories could add pounds to your body. Plus, a lack of sleep can also make you feel incredibly tired during the day, reducing the likelihood you will exercise.

The Importance of Sleep on Your Heart

Whether you are awake or asleep, your heart is pumping blood to all the tissues in your body. While your heart rate might be slower while you are asleep, the work your heart does during sleep is vital. Research suggests depriving your heart of the benefits of sleep can lead to a number of very serious problems.

In one study about the link between sleep and heart disease, highlighted by Science Daily, researchers asked 20 people to undergo heart tests both before and after a 24-hour period that included only three hours of sleep. Researchers found sleep loss caused the heart to beat harder, increasing both systolic and diastolic blood pressure readings. It is reasonable to think long-term exposure to this kind of damage could result in decreased heart capacity, also known as heart disease.

A lack of sleep can also cause tissues within the heart to swell. This is especially true for women. Women who sleep less than six hours per night have more heart inflammation than men who do not sleep well, according to the American Heart Association.

Inflammation like this is linked to heart disease and also to a risk of stroke.

The Drawbacks of Snoring on the Heart

For some people, poor sleep is caused by snoring. Snoring is indicative of an inability to pull air into the lungs during sleep. According to research published in the American Journal of Cardiology, snoring is associated with a modest increase in the risk of cardiovascular disease and stroke.

Researchers report snoring can be caused by a number of things, such as:

  • High blood pressure
  • Existing heart disease
  • Diabetes
  • Metabolic syndrome

But this research suggests snoring can also contribute to the development of serious disease, especially ones that impact the heart.

The Importance of Sleep on Your Immune System

Just as the body heals tissues during sleep, it also works to fight infections.

In an overview of sleep research, published in the American Journal of Clinical and Experimental Immunology, researchers report a lack of sleep can make the immune system less efficient, potentially allowing viruses to sneak into the body undetected. At the same time, when a person has an illness, such as a cold, they tend to sleep less.

Put together, this suggests a lack of sleep could make you sick, and while you are sick, you will experience a lack of sleep that could exacerbate symptoms. This feedback loop could continue unless you take steps to address the issues that keep you from sleeping.

The immune system works, in part, by sending out specific cells in response to a threat. When a virus or some other infectious agent enters the body, the immune system releases cells that surround and destroy the invader before it has a chance to take over the entire body.

This is a very coordinated system, and research published in the journal Pflugers Archiv suggests that it breaks down with a lack of sleep. The report suggests helper cells do not move as quickly when people experience a lack of sleep, allowing an infection to spread and grow faster.

Your immune system works at a subconscious level, so there is nothing you can say or do to help it work more efficiently. But clearly, getting more sleep could be key to helping you both avoid infections and fight them when you have them.

Lack of Sleep and Your Emotions

A good night’s sleep can leave you feeling relaxed, refreshed, and ready for the next day. A lack of sleep over a long period of time, on the other hand, can leave you feeling frazzled and upset.

According to the National Sleep Foundation, people with ongoing and untreated insomnia have a two to 10 times higher risk for an episode of major depression when compared to people who sleep well.

Accident Risks and Low Quality of Sleep

The things we do every day, without even thinking about them, rely on fine-tuned reflexes and an attentive mind. When you aren’t getting the sleep you need, tackling these tasks can be difficult.

Consider driving. In order to move your car safely from one point to another, you must:

  • Control the machinery of the car, including wheels and pedals.
  • Know where your car is in space.
  • Know where other cars are.
  • Pay attention to signals and lights.
  • Follow a specific route.

When you don’t get enough sleep, one or more of these simple tasks could be difficult or impossible to get right, and that could lead to an accident.

A study in BMC Medicine found that people who slept six hours per night were 33% more likely to be involved in a car crash when compared to people who slept seven to eight hours per night. That result held true even if the person didn’t report feeling sleepy during the day.

Clearly, a lack of sleep has an impact on the ability to handle driving tasks. Similar research suggests that sleep deprivation could also impair your ability to handle sensitive tasks at work.

Research shows sleep-deprived workers are 70% more likely to participate in a work accident.

To learn more about the risks of sleep-related accidents (and how to prevent accidents), visit our article on comatose commuters.

How Much Sleep Do You Need?

We have discussed the risk of low sleep throughout this article. You might be wondering how much sleep you should get in order to stay as healthy as possible. In general, research suggests that people need at least seven hours of sleep per night.

In a study published in the journal Current Cardiology Reviews, scientists examined several studies linking poor sleep with an early death. In one study the team cited, researchers found that people who slept seven to eight hours per night were less likely to experience:

  • Heart disease
  • Cancer
  • Stroke

This is a fascinating bit of data, as it suggests getting enough sleep on a regular basis could allow you to live longer.

According to the National Sleep Foundation, the amount of sleep you need depends on your age. For example, healthy teenagers require eight to 10 hours of sleep per night while adults ages 26 to 64 need seven to nine hours of sleep per night.

how age impacts sleep

Even then, experts say, your individual need for sleep might be different than the people around you. It turns out your personality type may have something to do with how much you sleep at night, as well. Assess your daytime sleepiness to determine whether or not you are getting enough rest. You may be sleep deprived if you fall asleep while you are:

  • Riding for one hour in a car with no stops.
  • Watching television.
  • Reading books or magazines.
  • Sitting still while in a meeting or classroom.

You can also document when you went to bed, when you woke up, and how you felt when you woke up. A pattern could emerge that makes it clear that you need to focus on improving your sleep.

Preparing Your Room to Help You Sleep Better

What can you do if you’re not getting the sleep you need? Start by examining the room you use for sleeping. A few choice updates could help you make your room a safe haven for sleep.

In general, your bedroom should be optimized for sleeping. The better we optimize our bedroom for sleep, the more ready we are for the rise and grind of the next morning. That means you should not have televisions, computers, exercise machines, sewing machines, or other non-restful items in the room where you sleep. When you walk into your bedroom, your brain should register that you are preparing for sleep. If you do have a TV in your room, try not to watch TV before bed.

Johns Hopkins Medicine reports that most people sleep soundly in rooms kept between 65 and 69 degrees. If you have a separate thermostat for the bedroom, adjusting to this setting could be helpful. If not, try turning down the heat throughout the house an hour or two before bed.

Also, keep your sleeping space as dark as possible. Bright lights, whether they come from street lights or the sun, can prompt your brain to stop your sleep session. Removing that light signal could be key to keeping you asleep.

Lights on the blue spectrum should also be removed from your bedroom. According to Harvard Medical School, lights on the blue spectrum can suppress the release of melatonin, a natural chemical your body releases when bedtime arrives. That means glancing at a computer screen, a tablet, a smartphone, or an LED light bulb could all interfere with chemical signals that make you sleepy. You could be awake for additional hours as a result.

Bedtime companions, such as stuffed animals or a favorite blanket, have also been shown to reduce stress and anxiety in children and adults which can promote a better night’s sleep.

Stop Snoring, Start Sleeping Better

A partner with a snoring issue can interrupt your sleep, especially if the only way to make the noise stop involves a poke or prod from you. Shifting to a two-bedroom system could help everyone to get a good night’s sleep. Adjustable beds may be the best option, as the ability to raise the head can significantly reduce snoring.

But, it isn’t just a companion whose snoring may affect your quality of sleep. If you snore, it may mean you are not getting enough oxygen as you sleep. People who snore often wake themselves up, or have a more difficult time going through all the stages of sleep.

Sleep Apnea and Sleep

If your sleep is interrupted by frequent bouts of snoring, and you often awaken feeling as though you are gasping for air, you could be dealing with sleep apnea. This condition causes your airways to close while you are sleeping, and it can put intense pressure on your cardiovascular system. Your body awakens you because it needs oxygen it just isn’t getting.

A continuous positive airway pressure (CPAP) machine is made to address sleep apnea. A machine like this provides you with pressurized air, so your airways stay open and your tissues get the nourishment they need as you sleep.

According to the National Sleep Foundation, it can take up to two weeks to feel all of the benefits of a CPAP machine, and some people still struggle with the idea of wearing a mask with blowing air all night long. But doctors will adjust the humidity, pressure, and placement of the mask to help with comfort.

Sleeping Well on the Road

Many of the sleep hygiene tips we have discussed concern changes you can make to your home environment. But for some of us, travel is a part of everyday life. While it is much harder to control what happens with your sleep while you are away from home, there are some common sense tips you can follow to ensure your trip doesn’t interfere with your sleep.

If you travel far from home, you may have a shift in time. Your body may believe it is 8 a.m., for example, but all the clocks around you may read 1 p.m. This disconnect between your internal clock and external reality is known as jet lag.

The National Sleep Foundation suggests that you can blunt the impact of jet lag by:

  • Shifting to the new time zone at home before your trip begins.
  • Changing your watch to your destination time zone as soon as you board the plane.
  • Staying in the sunshine as much as possible when you arrive.
  • Staying awake until 10 p.m. local time when you arrive.
  • Eating a light snack, not a heavy meal, when you arrive.

jet lag and the importance of your sleep

When you settle down to sleep for the first night at your destination, you may struggle to stay asleep. Research highlighted by Smithsonian suggests that our brains are hard-wired to stay in lighter levels of sleep when we are resting in a new place. This could be an evolutionary advantage. Our ancestors wanted to see threats when they arrived. But it could seem like a distinct disadvantage if you need to rest in your new spot.

Bring familiar pillows or blankets with you. Also, arriving a day early if you have an important meeting to attend allows you to get at least one day of rest before you are required to perform on your trip.

How Your Diet Affects Your Quality of Sleep

Eating a large meal before bedtime can increase a sense of fatigue and sleepiness, but the work your body must do to digest food can also prompt you to stay awake even when you want to rest. Most experts recommend avoiding a heavy meal close to bedtime. But new research suggests that the foods you eat and the beverages you drink may also impact your sleep, no matter when you take these substances in.

In a study published in the Journal of Clinical Sleep Medicine, researchers asked 26 people to follow a controlled diet for four days, and on the fifth day, participants could eat anything they wanted to eat. On the fifth day, participants took longer to fall asleep, and they spent more time in the early stages of sleep. People who ate carbohydrates and other sugars were more likely to awaken throughout the night. People who ate more fiber spent more time in deeper stages of sleep.

This is a small study, but it suggests a high-sugar diet has negative effects on sleep. Limiting sugars and adding in fiber could help boost your quality of sleep.

beverages to drink before sleep

What should you consume instead? A study from the journal JAN suggests chamomile tea. In this study of 80 women, those who drank chamomile tea reported fewer sleep difficulties.

Since sleep difficulties and obesity are closely related, as we have discussed, it might also be wise to shift an eating plan to allow for weight loss. Swapping out high-calorie items for less dense options could allow you to shed pounds, which could help you sleep more comfortably.

What Else Can You Try?

Another aspect which relates directly to sleep is the relationship between exercise and sleep. While both are seen as important pillars of health, it is only recently that research has shown how increasing one can also increase the other.

We hope we have demonstrated how closely sleep quality relates to your health, and we have given you a few ideas you can use to improve your sleep. If these suggestions do not help, a visit with the doctor may be in order. Some medical conditions can have an impact on your ability to sleep and getting those issues addressed could be just what you need in order to feel rested in the morning.

You might also look at the mattress you’re sleeping on. In a study in the International Journal of Industrial Economics, researchers found that people spent more time in restorative levels of sleep when they were resting on mattresses they rated as “comfortable.” When there was a match between the mattress feel and their preferred mattress type, they slept more soundly.

Mattress selection is deeply personal. The mattress you love might not be right for someone else. That’s why we recommend taking your selection process seriously. Do your homework and make sure you’ve made the right choice for you.

We can help. We have amassed articles on specific types of mattresses, mattress selections for certain sleeping preferences and needs, and more. We have written about the new trend of buying a bed in a box and finding the best mattress in a store vs finding the best online mattress. Browse our resources and make an informed decision. You will thank yourself in the morning.


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Medical Disclaimer: The information contained on the site should not be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for informational purposes only.

1 thought on “The Importance of Sleep: An Ultimate Guide to Sleep and Health”

  1. Who is behind this site? Good information but readers need to be able to gauge its validity by being informed of possible vested interests. Transparency is much appreciated and a lot of work went into the site so why not maximixe impact?

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