Non-REM Sleep

Non-REM sleep (non-REM sleep) is one of the sleep stages classified by changes in brain waves during sleep, and is the counterpart of REM sleep (REM sleep).

Characteristics of Non-REM Sleep

• Brain rest:

  • Non-REM sleep is a state in which the brain is resting and plays an important role in recovering from brain fatigue.

  • Brain waves become larger in amplitude and longer in wavelength as sleep deepens.

• Body rest:

  • Heart rate, respiratory rate, body temperature, blood pressure, etc. decrease, and the body enters a resting state.

  • Muscle tension also loosens, and the body becomes relaxed.

• Sleep depth:

  • Non-REM sleep is further divided into four stages (stages 1 to 4) depending on the depth of sleep.

    • Stage 1: Light sleep immediately after falling asleep

    • Stage 2: A deeper state of sleep

    • Stages 3 and 4: The deepest sleep, also known as "slow-wave sleep"

• Growth hormone secretion:

  • Growth hormone is actively secreted, especially during deep non-REM sleep, promoting body repair and growth.

Role of Non-REM Sleep

• Recovery from brain and body fatigue:

  • Non-REM sleep rests both the brain and body and promotes recovery from fatigue.

• Improvement of immune function:

  • Secretion of growth hormone improves immune function and increases the body's resistance.

• Memory consolidation:

  • It is thought that information and memories gained during the day are organized and fixed during non-REM sleep.

Differences from REM Sleep

• REM sleep:

  • The body is resting, but the brain is actively working.

  • You often have dreams, and your eyes move rapidly (Rapid Eye Movement).

  • It is thought to be involved in memory organization and consolidation.

• Non-REM sleep:

  • Both the brain and body are resting.

  • Deep sleep, with active secretion of growth hormone.

Sleep Cycle

• Sleep is repeated in a cycle of about 90 minutes of non-REM sleep and REM sleep.

• Immediately after falling asleep, deep non-REM sleep appears, followed by light non-REM sleep and REM sleep.

• As the sleep time progresses, the proportion of light non-REM sleep and REM sleep increases.

For a Good Night's Sleep

• A good night's sleep with a balance of non-REM and REM sleep is essential for maintaining mental and physical health.

• It is important to establish regular lifestyle habits, moderate exercise, and a relaxing sleep environment.