Healthy Sleep

Source: MedlinePlus Health Topics, U.S. National Library of Medicine

Last synced 8/14/2026Status: primary verified

What is sleep? While you are sleeping your brain and body functions are still active. Sleep is a natural process that helps your body restore energy, supports learning and memory, and keeps you healthy. During sleep, your brain cycles through different stages of non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep. Non-REM sleep has three stages that range from light to deep sleep, while REM sleep is when most dreaming occurs. During each stage, your brain waves, breathing, heart rate, and body temperature change throughout the night. Certain phases of sleep help you: Feel rested and energetic the next day. Learn new information, get insight, and form memories. Give your heart and blood vessels a rest. Release growth hormone, which helps children grow and assists in muscle repair and tissue healing for everyone. Release sex hormones, which contribute to puberty and fertility. Maintain a healthy balance of hormones that control hunger and fullness. Strengthen your immune system by producing cytokines (hormones that help the body fight infection). You need all the stages to get a healthy sleep. How much sleep do I need? The amount of sleep you need depends on your age, lifestyle, health, and sleep patterns. The general recommendations for sleep are: Babies (4-12 months): 12-16 hours a day (including naps) Children (1-2 years): 11-14 hours a day (including naps) Children (3-5 years): 10-13 hours a day (including naps) Children (6-12 years): 9-12 hours a day Teens (13-18 years): 8-10 hours a day Adults (18 years and older): 7-9 hours a day During puberty, teenagers' biological clocks shift. They tend to fall asleep later and wake up later, which can conflict with the early school start times. This is one reason many teenagers don't get enough sleep. Some people think adults need less sleep as they age, but there is no evidence to support this. However, older adults often get less sleep or spend less time in the deep, restful stages of sleep. They al

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This information is for general education and is not medical advice. Always talk to a licensed U.S. clinician about your situation, medications, or treatment decisions.