Sleep is important because it supports nearly every major system in the body. Adults aged 18 to 60 generally need at least 7 hours of sleep each night. During sleep, the brain processes information and forms memories, while the body regulates hormones, supports immune function, repairs tissue and helps maintain heart and metabolic health. Too little sleep can affect concentration, mood, reaction time and physical health.
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What Does Sleep Do for Your Body?
Sleep helps the brain, heart, metabolism, immune system and tissues carry out their normal work.
| Area | Why sleep matters | What poor sleep can affect |
|---|---|---|
| Brain function | Supports learning, memory, attention and clear thinking | Concentration, decision-making and reaction time |
| Emotional health | Helps regulate mood and stress responses | Irritability, low mood and difficulty managing stress |
| Heart health | Helps the heart rate and blood pressure follow healthy daily patterns | Higher risk of high blood pressure, heart disease and stroke |
| Metabolism | Helps regulate hunger hormones and the body's response to insulin | Appetite changes, weight gain and poorer blood sugar control |
| Immune function | Supports the body's immune response | Greater susceptibility to some infections |
| Growth and repair | Supports tissue repair and physical recovery | Slower recovery and reduced physical performance |
Sleep Supports Learning and Memory
Sleep helps the brain process new information and form long-term memories. Poor-quality or insufficient sleep can make it harder to focus, learn, think clearly and perform tasks safely.
Sleep Helps Protect Physical Health
During sleep, heart rate and blood pressure generally decrease, giving the cardiovascular system time to recover. Regularly getting too little sleep is associated with a higher risk of high blood pressure, obesity, heart disease and stroke.
Sleep also affects metabolism. Inadequate sleep can change hunger-related hormones, reduce the body's ability to respond to insulin and make it more likely that a person will eat high-calorie foods.
Sleep Supports Immune Function
Sleep affects immune activity. People who do not get enough sleep may be more likely to develop certain infections, so sleep forms part of the body's normal defense and recovery processes.
Sleep Affects Mood and Emotional Wellbeing
Adequate sleep helps regulate emotions and support alertness during the day. Sleep loss can make stress harder to manage and affect mood, judgment and social interactions. Long-term sleep deficiency is also associated with mental health problems, including depression.
How Much Sleep Do You Need?
Sleep needs depend on age. The general recommendations are:
| Age | Recommended sleep |
|---|---|
| Newborns, 0 to 3 months | 14 to 17 hours |
| Infants, 4 to 12 months | 12 to 16 hours, including naps |
| Toddlers, 1 to 2 years | 11 to 14 hours, including naps |
| Preschool children, 3 to 5 years | 10 to 13 hours |
| School-age children, 6 to 12 years | 9 to 12 hours |
| Teenagers, 13 to 17 years | 8 to 10 hours |
| Adults, 18 to 60 years | At least 7 hours |
| Adults, 61 to 64 years | 7 to 9 hours |
| Adults, 65 and older | 7 to 8 hours |
These figures are general recommendations. Sleep quality, regularity and timing also matter. The number of hours spent in bed is only one part of healthy sleep.
Is Sleep Quality as Important as Sleep Duration?
Yes. Healthy sleep depends on getting enough sleep, staying asleep, sleeping at an appropriate time and following a regular schedule. Seven hours of broken sleep may not provide the same benefits as seven hours of continuous, restorative sleep.
Frequent waking, loud snoring, gasping during sleep, persistent insomnia or feeling unrefreshed after enough time in bed may point to a sleep problem. Speak with a healthcare professional if these issues happen regularly.
How Can You Protect Your Sleep?
A regular schedule and daytime habits can help:
- Keep a consistent bedtime and wake-up time, including on weekends.
- Get natural light earlier in the day.
- Stay physically active during the day.
- Reduce bright artificial light before bedtime.
- Set aside enough time for sleep instead of treating it as optional.