What Happens During Sleep?
As anyone who’s ever woken up feeling like they never got any sleep knows, a good night’s rest is essential to mental and physical well-being. Yet getting a regular, quality night of slumber can be more difficult than you might think, especially in times of stress or with irregular schedules, and research shows that not getting enough sleep on a consistent basis raises your risk for many serious diseases and conditions.
For decades, scientists have worked to understand what exactly is happening during sleep and how it impacts health. What we now know is that sleep is a dynamic process that incorporates a range of behaviors and biological functions that can’t be fully captured by traditional measurements like brain waves or arousal. It is a natural state that combines voluntary decisions with involuntary biobehavioral changes, and it’s a powerful combination that can have lasting health consequences.
Before the 1950s, most people thought that sleep was a dormant time during which the body and brain were “at rest.” But this was a major misconception, as researchers have since discovered that there is a great deal going on in our bodies and brains during sleep. In fact, there are a number of critical processes that help us function properly during the day and throughout life, including consolidating memories, cleaning out proteins (like the amyloid and tau toxins associated with Alzheimer’s disease), and restoring our ability to learn.
A remarkably conserved behavioral state, sleep has been observed in a wide range of animal species, from zebrafish to fruit flies and rodents. During the sleep state, animals are quiescent and exhibit a reduced sensitivity to sensory stimuli. They also show a decrease in postural activity and a slowing of their movements. Other behavioral traits can be used to distinguish between waking and sleeping states, such as reduced arousal thresholds or the ability to be easily awakened from a sleep position.
The most important function of sleep may be in its role as a form of memory maintenance, which helps to keep information in our long-term memories. During sleep, the brain converts short-term memories into more stable forms, helping to make it easier for us to recall those events in the future. In addition, REM sleep is crucial for the formation of new memories and the consolidation of existing ones.
Sleep also helps maintain a healthy weight and reduces the likelihood of chronic illnesses such as heart disease, stroke, diabetes, high blood pressure and depression. And it is a critical part of the healing process after illness or surgery.
While the exact amount of sleep you need varies from person to person, most adults should aim for at least seven hours of sleep each night. If you’re struggling to get enough sleep on a regular basis, talk with your doctor or nurse. There are a variety of factors that can affect your sleep, from certain mental health issues to medications and even the environment you live in.