How Sleep Works

Sleep occurs in ~90-minute cycles with two main types - NREM and REM Sleep.

Both stages are essential. Short sleep robs you of deep NREM (if you go to bed late) or REM (if you wake early). Aim for 7–9 hours when possible. You can't fully "catch up" on weekends—sleep debt accumulates.

NREM (Non-REM) Sleep

Dominates early in the night, especially deep slow-wave sleep.

Clears brain toxins, consolidates memories/skills, repairs the body, releases growth hormone, reduces inflammation, and strengthens immunity.

REM Sleep

Increases later in the night.

Processes emotions, "soothes" painful memories, boosts creativity/problem-solving, and helps regulate mood and recognize facial expressions

Back to Sleep Resources

Walker, M. (2017). Why we sleep: Unlocking the power of sleep and dreams. Scribner.

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How Sleep Works

NREM (Non-REM) Sleep

REM Sleep ​

Increases later in the night. Processes emotions, "soothes" painful memories, boosts creativity/problem-solving, and helps regulate mood and recognize facial expressions

REM Sleep

Increases later in the night.

Processes emotions, "soothes" painful memories, boosts creativity/problem-solving, and helps regulate mood and recognize facial expressions