The Importance of Sleep

Adults aged 18 to 60 years are recommended to sleep at least 7 hours each night, otherwise, they run the risk of becoming sleep deprived. Ignoring the importance of sleep may have an impact on your overall health. If you make it a priority, your body will reap the benefits of sleep.

common symptoms of sleep deprivation

 Illustration by Emily Roberts, Verywell

When you sleep, your body produces proteins called cytokines that have immune-boosting effects and serve as fuel for your white blood cells. Lack of sleep decreases the production of cytokines and makes you more susceptible to bacteria and viruses.

Find your motivation to prioritize sleep by learning about why you need to get a good night's rest.

Sleep Is Restorative

When you sleep, you allow your body to repair and rebuild. During this time, the body is able to clear debris from the lymphatic system, which boosts the immune system.

While you sleep, there are many important processes that happen, including:

  • Muscle repair
  • Protein synthesis
  • Tissue growth
  • Hormone release

Sleep Reduces Stress

Sleep is a powerful stress-reliever. It improves concentration, regulates mood, and sharpens judgment and decision-making. A lack of sleep not only reduces mental clarity but our ability to cope with stressful situations. This is due, in part, to the impact of chronically high levels of cortisol.

Poor quality sleep or a lack of sleep altogether raises our cortisol levels. High cortisol levels are important in the short term, stimulating alertness and vigilance, raising heart rate and blood pressure, but over time it can cause systemic inflammation and disrupt our hormonal balance.

Typically, your cortisol levels fall in the evening hours, as one element of the body’s natural preparation for sleep. When we put off sleep, cortisol levels remain high and interfere with the release of melatonin, a hormone that is essential for the regulation of sleep-wake cycles.

Too little sleep impacts the rapid eye movement stage of sleep (REM) which governs our processing of emotions and memories. Losing out on the restorative benefits of REM sleep directly impacts our mood, making us more irritable and more stressed out.

Sleep Improves Your Memory

The link between sleep and memory processing is well established. Sleep serves as an opportunity for the mind to process all the stimuli that we have taken in while we are awake; and triggers changes in the brain that strengthen neural connections helping us to form memories. These memories can be accessed later on through a process called recall, that’s why teachers emphasize the importance of a good night’s sleep before taking a test.

It’s also important to note that while the link between sleep, learning, and memory are complex, we have all experienced the impact that a lack of sleep can have on our concentration and ability to learn efficiently so it's important to get a good quality of sleep not only to maximize our ability to acquire new information but also to recall the information later and share it with others.

Sleep is also vital to memory consolidation—the process of stabilizing our memories. Memory consolidation is important for learning new information. Numerous research studies find that sleep supports this process via a series of electrophysiological, neurochemical, and genetic mechanisms that take place during the slow-wave sleep stage of sleep. You actually don't need to sleep for a long time to get the benefits of improved memory. We enter slow-wave sleep pretty quickly after falling asleep so even a quick nap can help with our memory.

Sleep Helps You Maintain a Healthy Body Weight

When you are sleep deprived your body alters the hormones that regulate hunger and appetite. These hormones include:

  • Leptin: This hormone suppresses appetite and encourages the body to expend energy.
  • Ghrelin: This hormone triggers feelings of hunger.

Both of these hormones are thrown off when you are short on sleep—leptin goes down and ghrelin goes up.

To make matters worse, a recent study found that sleep deprivation can activate the endocannabinoid (eCB) system in our brain—the same areas activated by marijuana—that increase hunger and appetite. Stimulating the eCB reward system makes you more likely to crave junk food.  

You are also more likely to make unhealthy lifestyle choices when you are tired. It is not uncommon for people to drink sugary drinks to stay awake, get takeout instead of cooking, or skip out on exercise. Consuming these empty calories or putting off exercise may be ok from time to time, but if chronic fatigue sets in, this can lead to weight gain or the development of obesity or diabetes over time.  

Sleep May Prevent Illnesses

Sleep deprivation can have very detrimental health impacts and has been linked to chronic diseases such as diabetes and heart disease and can even lead to obesity.

Lack of sleep makes you more prone to illness because your immune system isn’t performing at its peak. A study found that people who averaged less than 7 hours of sleep were nearly three times more likely to develop a cold than their colleagues who were well-rested.

The insidious part about sleep deprivation is you don't often feel its negative effects until it’s too late. As you miss larger and larger amounts of sleep and go farther and farther through the stages of sleep deprivation, the damage increases. Organs need time to replenish and clear waste, as does your brain, and they do it when the rest of your body is resting.

Sleep Is Important for Your Mental Health

Evidence suggests lack of sleep contributes to the formation of new mental health problems and to the maintenance of existing ones, but the magnitude of its effect is difficult to estimate and may be different across mental health conditions.

Sleep problems are very common in those with mental illness. In fact, disrupted sleep is commonly seen as both a symptom and consequence of mental health disorders, although sleep deprivation is rarely treated as the cause of mental health conditions.

The most common sleep problem associated with poor mental health is insomnia, which is sustained difficulty falling or staying asleep. Insomnia has been found to worsen most mental health disorders, especially paranoia and hallucinations. 

If you’re finding it hard to sleep, stay asleep, or if you’re only able to sleep for a short amount of time you may be experiencing insomnia. 

Symptoms of insomnia include:

  • Not feeling well-rested after a night's sleep
  • Daytime tiredness or sleepiness
  • Irritability, depression or anxiety
  • Difficulty paying attention, focusing on tasks or remembering
  • Increased errors or accidents
  • Ongoing worries about sleep

You may experience insomnia for a number of reasons, but the most common culprits are: 

  • Stress
  • Work schedule
  • Poor sleep habits
  • Excessive alcohol or caffeine use at night 
  • Habitual nighttime screen use

Verywell / JR Bee

It is not uncommon for people to report difficulty sleeping if they are agonizing over work, school, health, finances, or family. Stressful life events or trauma—such as the death or illness of a loved one, divorce, or a job loss—may also increase your chances of experiencing insomnia. If you are experiencing insomnia you may also want to take a closer look at your mental and emotional health. Insomnia may be contributing to your mental health problems and you may feel significantly better after addressing it.

How to Improve Your Sleep

Given the importance of sleep to our health, there is no time better than now to make some lifestyle changes that will get you the 7 or more hours you need. Small changes to your nighttime routine can result in a huge health benefit. These include the following:

  • Establish a realistic bedtime and stick to it every night, even on the weekends.
  • Maintain comfortable temperature settings and low light levels in your bedroom.
  • Consider a “screen ban” on televisions, computers and tablets, cell phones, and other electronic devices in your bedroom.
  • Abstain from caffeine, alcohol, and large meals in the hours leading up to bedtime.
  • Refrain from using tobacco at any time of day or night.
  • Exercise during the day; this can help you wind down in the evening and prepare for sleep.

A Word From Verywell

Sleep is vital to our health but it may not be possible for all people to get 7 or more hours. For parents spending an hour with their child at the beginning or end of the day may be well worth the tradeoff of sleep. The best way to maintain a healthy life is to take a wholistic approach. Monitor how you feel and be sure to create a schedule that emphasizes social connectedness, routine exercise, healthy eating, and rest.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the american academy of sleep medicine and sleep research societySLEEP. Published online June 1, 2015. doi:10.5665/sleep.4716.x

  2. Tucker MA, Humiston GB, Summer T, Wamsley E. Comparing the effects of sleep and rest on memory consolidation. Nature and Science of Sleep. doi:10.2147/NSS.S223917

  3. Rasch B, Born J. About sleep’s role in memoryPhysiological Reviews. 2013;93(2):681-766. doi: 10.1152/physrev.00032.2012 

  4.  Hanlon EC, Tasali E, Leproult R, Stuhr KL, Doncheck E, de Wit H, Hillard CJ, Van Cauter E. Sleep restriction enhances the daily rhythm of circulating levels of endocannabinoid 2-arachidonoylglycerol. 2016 Mar 1;39(3):653-64. doi:10.5665/sleep.5546

  5. Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB. Sleep habits and susceptibility to the common coldArch Intern Med. 2009;169(1):62–67. doi:10.1001/archinternmed.2008.505

  6. Scott AJ, Webb TL, Rowse G. Does improving sleep lead to better mental health? A protocol for a meta-analytic review of randomised controlled trials. BMJ Open. 2017;7(9):e016873. Published 2017 Sep 18. doi:10.1136/bmjopen-2017-016873

By Shamard Charles, MD, MPH
Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.