Sleep is a powerful force, yet one that is often overlooked. People spend more time worrying about their diets, exercise programs and stress levels than they do on their sleep habits — but getting enough quality rest is key to maintaining good health. Sleep is necessary for growth, healing, memory consolidation and supporting a healthy immune system. It also allows the brain to clear cellular and protein debris that can lead to neurodegenerative disorders.
Until recently, scientists thought that sleeping was a passive state in which the body and brain shut down. But more research has shown that, while parts of the brain do turn off, the body is still active, albeit in different ways during each stage of sleep.
There are many theories about why we need sleep, but the most prevalent is that it’s a form of repair and restoration. It’s been shown that, during the first non-rapid eye movement phase of sleep (deep sleep), the cells of the body are repaired and regenerated, whereas during the rapid eye movement (REM) stage, the brain is organizing and consolidating memories.
Scientists also know that during REM sleep, blood flow to the brain increases and neurons in the brain become more active, which helps form new memories. In addition, sleep is crucial for our emotions and moods. When we don’t get enough sleep, our emotions can become unstable and even depressed.
When we feel stressed, the hormone cortisol, which is produced by the adrenal glands, increases during waking hours and lowers during sleep. This may explain why people who get less sleep are more likely to develop depression and anxiety, as well as a higher risk of heart disease and other chronic illnesses.
A good night’s sleep can also help improve cognitive function — that is, our ability to think clearly and concentrate. Studies have shown that students who get adequate amounts of sleep perform better in school than those who don’t.
The amount of sleep needed varies from person to person, but most experts recommend between seven and eight hours each night. In general, young children and teenagers need more sleep than adults, and older adults need slightly less.
There’s no magic number of hours that will make you feel your best, but if you’re consistently getting less than you need, you should try to change this. You might find that you need more sleep as you age, or if your health is poor.
If you’re worried about your sleep, speak to a GP or a specialist, or check out our sleep guides for more information.