People who wake up during deep sleep may experience sleep inertia for 30 to 60 minutes. Sleep inertia: Sleep inertia describes the feeling of grogginess, disorientation, or a reduction in performance that can occur after waking up.What Happens if You Don’t Get Enough Deep Sleep?Īlthough it can be challenging for researchers to differentiate the effects of losing deep sleep from sleep deprivation in general, studies have found several potential consequences of insufficient deep sleep. In particular, these hormonal changes support the body’s ability to develop acquired immunity, remembering and better defending against specific pathogens. Fortifies the immune system: Hormonal changes during deep sleep enhance the immune system.Human growth hormone may also help the body regenerate cells and heal damaged tissue.

Heals damaged tissue: Deep sleep promotes the release of human growth hormone, which may support the development of muscle and other tissues in the body.

Supports memory consolidation: Researchers believe that during deep sleep the brain recalls new information learned during waking hours and transfers it to long-term memory.

This benefit may be related to deep sleep’s role in relieving the pressure to fall asleep, which builds during each waking hour.

Promotes feeling rested: Deep sleep is necessary to waking up feeling refreshed and renewed.

Deep sleep in particular appears to provide a number of important health benefits. The Importance of Deep SleepĪlthough scientists are still learning about the purpose and benefits of sleep, it’s clear that sleep impacts just about everything in the mind and body, from mood and immunity to overall health.

The percentage of time spent in deep sleep decreases as a person gets older. Until middle age, people spend about 10% to 20% of their total sleep time in deep sleep.

Periods of deep sleep are usually longer early in the night, likely because a person’s need for rest is highest just after falling asleep. Initial periods of deep sleep last around 20 to 40 minutes at a time. Sleepers are often hardest to wake up during stage 3 sleep and, if awakened, may experience a period of mental fogginess called sleep inertia. Stage 3 sleep is a period of deep muscle relaxation and is often perceived by sleepers as the most refreshing and high quality portion of sleep.ĭeep sleep is also called slow-wave or delta sleep, due to the characteristic brain waves that occur during this stage. During this sleep stage, a person’s heart rate, blood pressure, and breathing slow until they reach their lowest levels of the night. What Is Deep Sleep?ĭeep sleep refers to stage 3 of non-rapid eye movement sleep. We consider the benefits of this sleep stage, the risks associated with a lack of deep sleep, and tips for improving your sleep hygiene. Learning more about the function and importance of deep sleep can help you get the most out of your nightly rest. Each sleep stage is associated with certain physical processes and benefits, and people cycle through each of these stages several times during a night of sleep. Deep sleep is a term that describes stage 3 of NREM sleep. There are three stages of NREM sleep: stage 1, stage 2, and stage 3. There are two types of sleep: rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Although there are no definitive guidelines for how much deep sleep you need, experts say that most adults need between seven and nine hours of sleep each night. Deep sleep describes a particular stage of sleep that is important for waking up feeling refreshed and alert.

Not getting deep sleep