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Why Sleep Is Important: 9 Health Benefits of Good Sleep

Updated · 5 min read · By Taohidul Islam

Sleep is important because almost every system in your body depends on it. Good sleep helps you learn and remember, keeps your mood steady, supports your immune system, heart and blood sugar control, helps regulate appetite, and keeps you alert enough to stay safe. Most adults need at least 7 hours a night to get these benefits.

What happens while you sleep

Sleep is not a switched-off state. Through the night you cycle through light sleep, deep sleep and REM sleep, and your brain and body stay busy the whole time. Deep sleep is linked with physical repair, REM with dreaming, and both are thought to play a part in memory. Our guide to sleep stages explains each one.

9 health benefits of good sleep

1. Better learning and memory

Sleep helps your brain form and maintain the pathways that let you learn and create new memories. According to the National Institute of Neurological Disorders and Stroke, without enough sleep you cannot form or keep those pathways well, and memory consolidation most likely relies on both non-REM and REM sleep.

2. Sharper focus and decision-making

Sleep supports attention, problem-solving, decision-making and creativity. Too little sleep changes activity in parts of the brain involved in these skills. Losing just 1 to 2 hours a night over several nights can affect how well you function about as much as going a day or two without sleep.

3. Steadier mood

Short sleep makes people more irritable and frustrated and less able to manage emotions or read other people's feelings. Ongoing sleep deficiency is also linked to depression. Feeling short-tempered after a bad night is one of the most common, and most reversible, effects of missing sleep.

4. A stronger immune system

Ongoing sleep loss can change the way your body defends itself against germs, making common infections harder to fight. In one study, healthy adults were given a cold virus after their sleep was measured for a week. Those sleeping less than 6 hours a night were more than four times as likely to develop a cold as those sleeping more than 7 hours.

5. A healthier heart and blood pressure

Sleep helps your heart and blood vessels heal and repair. Adults who regularly get enough sleep have a lower risk of high blood pressure, and good sleep is linked to lower risk of heart disease and stroke. Untreated sleep disorders can also raise the risk of heart problems.

6. Better blood sugar control

Insulin is the hormone that controls blood sugar. Not getting enough sleep can lead to higher-than-normal blood sugar, which may raise the risk of type 2 diabetes.

7. Appetite and weight regulation

Sleep helps balance the hormones that control hunger. When you are short on sleep, levels of ghrelin (which makes you feel hungry) go up and levels of leptin (which makes you feel full) go down. Adults who regularly get enough sleep have a lower risk of obesity.

8. Growth and physical repair

Deep sleep triggers the release of a hormone that supports normal growth in children and teens. In adults, sleep also helps maintain muscle mass and repair cells and tissue, which is part of why rest matters for recovery after exercise.

9. Safety on the road and at work

Sleep-deprived people react more slowly and make more mistakes. Drowsy driving can impair you as much as, or more than, being drunk, and people can slip into "microsleeps" of a few seconds without realising it. In older adults, poor sleep may also be linked with more falls.

How much sleep do you need?

The CDC recommends the following amounts per day:

AgeRecommended sleep
Newborn (0-3 months)14-17 hours
Infant (4-12 months)12-16 hours, including naps
Toddler (1-2 years)11-14 hours, including naps
Preschool (3-5 years)10-13 hours, including naps
School age (6-12 years)9-12 hours
Teen (13-17 years)8-10 hours
Adult (18-60 years)7 or more hours
Adult (61-64 years)7-9 hours
Adult (65 and older)7-8 hours

Quality matters as well as quantity. Waking often, or sleeping at very different times from day to day, can leave you tired even if the hours add up.

Signs you are not getting enough sleep

  • Needing an alarm every day and struggling to get up
  • Feeling sleepy during meetings, reading or driving
  • Relying on caffeine to get through the afternoon
  • Sleeping much longer on days off
  • Being more irritable or forgetful than usual

Key takeaway: sleeping in at weekends may not make up for sleep missed during the week. A regular schedule with enough time in bed every night is what delivers the benefits above.

Simple ways to sleep better

  • Wake up at the same time every day, including weekends.
  • Set a bedtime early enough to allow at least 7 hours of sleep.
  • Get daylight in the morning and stay active during the day.
  • Avoid caffeine in the afternoon and evening, and alcohol before bed.
  • Turn off screens at least 30 minutes before bed and keep the bedroom dark, quiet and comfortable.
  • If you cannot fall asleep after about 20 minutes, get up and do something quiet in dim light until you feel sleepy.

Regular exercise helps too. Our article on exercise and sleep covers how much and when.

When to talk to a doctor

See a doctor if you have had trouble falling or staying asleep for several weeks, feel very sleepy during the day despite enough time in bed, snore loudly, or have been told you stop breathing or gasp in your sleep. Most sleep problems can be treated.

Keeping an eye on your sleep with FitRest

If you wear an Apple Watch to bed, FitRest shows how long you slept, your sleep stages, and how your sleep compares with the target you set. Sleep consistency and the sleep trend make it easy to see whether your schedule is steady over weeks, and an optional bedtime reminder helps you get to bed on time. More on the sleep tracking page.

Sources

FitRest is a wellness app, not a medical device. It does not diagnose, treat or prevent any condition. Talk to a qualified health professional about any health concern.

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