The Importance of Sleep

There’s nothing quite like waking up rested after a good night’s sleep. The difference can feel immense and leave you feeling refreshed. Sleep is one of the most vital and complex body processes. It plays a crucial role in good mental health and healthy physical health, especially during childhood and adolescence. Research shows that getting enough high-quality sleep supports healthy brain function, maintains a strong immune system and keeps your heart and blood vessels healthy. Insufficient or inconsistent sleep can increase your risk for a number of chronic (long-term) health problems and may impact your ability to think, react, work and learn.

During sleep, there is a general reduction in activity across the entire body, including in the muscles and the brain. In humans and some other mammals, this is reflected by the characteristic horizontal posture associated with sleep. Other behavioral, motor and sensory criteria also distinguish sleep from wakefulness. In humans, a sleeper must show signs of “detachment” from the environment in order to be considered asleep, such as closed eyelids, reduced awareness of the surroundings and an absence of overt goal-directed behavior. Three additional defining characteristics of sleep-reversibility, recurrence and spontaneity-distinguish it from a state like hibernation or coma.

The sleep cycle lasts about six or seven hours, although in some people, it can be longer or shorter. Each cycle includes four stages of sleep-non-rapid eye movement (NREM) and rapid eye movement (REM). Each stage has a different pattern of brain waves and muscle activity. The first NREM period lasts the longest, followed by REM sleep and then slow-wave sleep. In children and adolescents, a significant proportion of the time is spent in NREM sleep.

Sleep is thought to be necessary to maintain your physical health and ward off disease, but it is not clear why you need sleep. One theory is that during sleep your body releases chemicals needed to repair cells damaged by everyday activities, such as exercise and illness. Insufficient or irregular sleep can lead to an increased risk for many health conditions, such as diabetes, cardiovascular disease and obesity. Moreover, poor-quality sleep increases your risk of developing mental health conditions, such as depression and bipolar disorder.

While some people are naturally good at sleeping well, most need to learn how to achieve sufficient high-quality sleep. The key is to develop a regular sleep schedule and maintain a consistent bedtime and wake-up routine. Other important factors include avoiding caffeine and other stimulants before bed, relaxing before sleep and maintaining a cool, dark room.

Most adults need between six and nine hours of sleep per night. However, this varies widely among people and may change depending on age, activity level, lifestyle and other health issues. Younger people and adolescents tend to need less sleep than adults, partly because of social schedules and late-night activities. Moreover, some sleep disorders, such as snoring and interrupted breathing, may interfere with the quality of sleep. Adults who suffer from such disorders should seek help.