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Sleep Cycle Stages: 8-Hour Night

4-5 cycles of N1/N2/N3/REM across 8 hours; deep sleep front-loaded, REM back-loaded.

A free, animated sleep cycle stages: 8-hour night you can read here or embed on any website, from Scrollchart.

Sleep Cycle Stages: 8-Hour Night

Sleep Cycle Stages: 8-Hour Night4-5 cycles of N1/N2/N3/REM; deep sleep front-loaded, REM back-loadedAwakeREMN1N2N301h2h3h4h5h6h7h8hHours of sleep

Eight-hour hypnogram staircase with 4-5 cycle boundaries marked. Stage bands: Awake, REM, N1, N2, N3. Deep N3 dominates cycles 1-2; REM bouts lengthen from ~10 min in cycle 1 to ~40 min in cycles 4-5. Cycle durations labeled ~90 min each.

Good for

  • Sleep explainer articles
  • Sleep tracker context pages
  • Why sleep duration matters content

Source & accuracy

This sleep cycle stages: 8-hour night is an editorial illustration built to represent the concept accurately. Where it shows figures, they are typical or representative values chosen to make the relationship clear, not a single underlying dataset. The diagram and its explainer are reviewed and maintained centrally, and updated over time as understanding improves.

What one sleep cycle contains

A typical night moves through repeating cycles of roughly 90 minutes, though individual cycles range from about 70 to 120 minutes. Each cycle passes through non-REM stages N1 (light transition), N2 (the bulk of sleep, marked by sleep spindles and K-complexes), and N3 (slow wave or deep sleep), then into REM sleep where most vivid dreaming occurs.

Most adults complete four to five cycles across an eight-hour night, but the cycles are not identical copies of each other.

Why deep sleep comes first and REM comes later

Slow wave sleep is front-loaded: the deepest N3 dominates the first one or two cycles, which is part of why an early-night awakening can feel especially groggy. As the night progresses, N3 shrinks and REM periods lengthen, so the longest REM bouts occur toward morning.

This explains why cutting sleep short by waking early tends to remove a disproportionate share of REM. General educational information only.

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Reference

What this is
A free, embeddable, animated sleep cycle stages: 8-hour night for any website.
Who uses it
Health blogs, Wellness sites, Biohacker blogs, Medical educators.
How to embed
Copy one line of HTML. No signup. No watermark. Works in WordPress, Webflow, Ghost, Substack, plain HTML.
File size
iframe embed, ~80 KB gzipped (loads on demand, does not block your page paint).
License
Free forever. Editorial explainer text included; updated centrally over time.
URL
scrollchart.com/diagram/sleep-cycle-stages

Embed format options

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Frequently asked questions

Where can I get a free animated "Sleep Cycle Stages: 8-Hour Night" for my website?
Scrollchart provides "Sleep Cycle Stages: 8-Hour Night" as a free, embeddable animated diagram you can add to any website with one line of HTML. No signup is required and there is no watermark. The diagram and its explainer text are served from scrollchart.com, so the embed stays current without any maintenance on your end.
How do I embed a sleep cycle stages: 8-hour night diagram in a health or wellness blog?
Copy the HTML snippet from the Scrollchart diagram page and paste it into any post or page in your CMS. It works in WordPress, Webflow, Ghost, Substack, and plain HTML without any plugin or account. The diagram renders as animated SVG directly in your page, so search engines can index the accompanying explainer text.
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