Why Sleep Matters
Sleep is not wasted time. A short guide to what happens while we rest.
People spend about a third of their lives asleep, and for good reason. During sleep the body repairs tissues, the immune system works and the brain organises memories from the day.
Sleep occurs in cycles of roughly 90 minutes, moving through light sleep, deep sleep and REM (rapid eye movement) sleep, when most vivid dreaming happens. Deep sleep is important for physical recovery, while REM sleep is linked to learning and emotional processing.
Most adults do best with seven to nine hours of sleep a night, though needs vary by age and person. Children and teenagers need more. Regularly sleeping too little is associated with poorer concentration, mood and long-term health.
Healthy habits can help: go to bed and wake up at about the same time each day, keep the bedroom dark, quiet and cool, avoid caffeine late in the day, and put screens away before bed. This article is general information, not medical advice; anyone with persistent sleep problems should talk to a doctor.