Sleep is an important time for the brain. Levels of brain activity change in each stage of sleep — including both rapid eye movement (REM) and non-REM (NREM) sleep — and evidence increasingly suggests that sleep enhances most types of cognitive function.

Getting enough hours of high-quality sleep fosters attention and concentration, which are a prerequisite for most learning. Sleep also supports numerous other aspects of thinking including memory, problem-solving, creativity, emotional processing, and judgment.

For people with sleep deprivation, insomnia, sleep apnea, or other conditions that prevent getting adequate rest, short-term daytime cognitive impairment is common. In addition, multiple studies have linked poor sleep with longer-term cognitive decline, including the development of dementia and Alzheimer’s dementia.

Thankfully, there is evidence that improving sleep can boost both short- and long-term cognitive performance. Better sleep can promote sharper thinking and may reduce the likelihood of age-related cognitive decline.

What Happens to the Brain During Sleep?

During a typical night of sleep, an individual goes through four to six sleep cycles that range from 70 to 120 minutes each. Both the brain and body experience distinct changes during these cycles that correspond to individual stages of sleep.

During NREM stages, brain activity slows overall, but there remain pulses of specific types of brain waves. This pattern of brain waves is most pronounced in stage 3 NREM sleep, which is also known as slow-wave sleep or deep sleep.

In contrast, REM sleep is marked by a sizable uptick in brain activity. In many ways, the brain’s activity during REM sleep is similar to when you’re awake. Not surprisingly, REM sleep is known for more vivid and involved dreaming.

It’s normal to cycle through both NREM and REM stages, with REM sleep being more concentrated in the second half of the night. During each part of this process, different chemicals in the brain become activated or deactivated to coordinate rest and recovery.

Experts still aren’t exactly certain why sleep proceeds in this pattern, but it is believed that it facilitates mental recovery, which can unlock cognitive benefits related to attention, thinking, and memory.

GIVE THE GIFT OF SLEEP: HEALY WATCH