The Importance of Sleep

It’s hard to overstate the importance of sleep. It’s a time when muscles repair themselves, the brain sweeps out waste and processes memories. It’s a time when hormones are released that control everything from our appetite to stress levels. And, as we now know, it’s also a time when the immune system fights off illness and infection. In fact, a growing body of evidence suggests that getting adequate amounts of sleep is among the most powerful factors in maintaining human health. It is well understood that getting enough sleep can help reduce the risk of heart disease, high blood pressure and diabetes, as well as depression and other mental illnesses. And it’s now a recognized fact that sleep is also crucial to the body’s ability to fight off disease and heal from injury.

Scientists have known for a long time that sleep is a distinct state characterized by the appearance of specific electrical patterns in the brain. These are the hallmark of the different stages of sleep, from rapid alpha waves to slower theta waves and finally the deepest phase of slow wave sleep (NREM).

As people drift into sleep, neuronal signaling progressively slows down until it eventually comes to a stop. This loss of neuronal activity is reflected in the onset of the characteristic transient sense of unresponsiveness so typical of sleep. In the past, this lack of responsiveness was attributed to a temporary “gating” of sensory inputs through thalamic relays, which prevents them from reaching the neocortex during sleep (Carskadon and Dement, 2005).

In recent years, however, scientists have discovered that this mechanism may not explain the full picture of sleep’s unique features. In particular, it has been found that during sleep there are local alterations in neural activation that appear to underlie interindividual differences in cognitive performance and memory (Hudson et al., 2022).

During the deeper stages of sleep, the brain appears to consolidate memories and strengthen them in ways that are similar to how learning occurs. During sleep, the brain is also believed to process new information and generate creativity. Indeed, a recent study of sleep and art found that individuals with greater creativity were able to solve visual puzzles faster when they were well rested.

It’s important to remember that sleep isn’t a one-size-fits-all phenomenon and that customary sleep practices vary by culture. For example, people across the world commonly take short naps during the day, whether it’s a Spanish siesta or an invigorating Japanese nap known as an “inemuri.” Whatever your sleep habits, the bottom line is that restful and uninterrupted nights of sleep are critical to keeping you healthy.