How Sleep Affects Your Health and Wellbeing

Your sleep cycle may seem like a passive activity, but it’s actually at the heart of the many restorative processes that are critical for your mental and physical health. While you slumber, your muscles repair themselves, your brain sweeps away waste and you form and consolidate memories—all vital functions that support your body’s immune system and enable it to heal from injury and disease. In addition, your slumber is a key time for your emotions to catch up, helping you cope with stress and boosting your resilience. But it’s not just your emotional and mental wellbeing that’s affected by poor sleep; getting enough slumber can also help prevent heart disease, diabetes and weight gain, and reduce the risk of a variety of chronic diseases, including cancer.

The slumber-and-wake cycle is a fundamental part of your life, yet it’s one that’s often taken for granted. In fact, the vast majority of Americans don’t get the recommended amount of sleep every night. The average person spends about 7 to 8 hours in deep sleep each night and an additional 30 minutes to an hour in REM (dream) sleep, for a total of roughly 90 minutes to two hours per cycle.

Sleep has long been a subject of scientific inquiry, and the field of sleep medicine is one of the fastest-growing areas in medicine. There’s a reason for that: research has revealed that slumber is essential to your health and wellbeing—and that not getting enough of it can lead to a host of problems, from depression and anxiety to obesity, high blood pressure and heart disease.

As researchers continue to investigate how sleep affects our mind and body, it’s becoming clear that there are three main dimensions to defining sleep: physiological, behavioral and subjective. Physiological criteria include specific patterns of brain activity, eye movement and muscle atonia. For example, when your eyes move rapidly behind your closed lids during REM sleep and brain waves are similar to those seen in wakefulness, it’s generally agreed that you’re in the sleep phase.

Behavioral and subjective criteria may be difficult to apply to a complex and highly individual process like sleep, but these are the underlying definitions that researchers use to characterize different sleep stages. This helps to ensure consistency between studies.

In a study published in Science Advances in December 2021, researchers found that sleeping for a full night improved cognitive function and reduced the levels of the hormone C-reactive protein associated with inflammation in the brain. That same study also found that a good night’s sleep may boost creativity by encouraging the brain to reorganize and restructure previously stored information. That’s why it’s important to get a good night’s sleep before you pick up the easel and paintbrushes or pick up a pen and paper to write.