Sleep Architecture & Future Disease Risk<\/p>\n
Source: PLOS Medicine, September 17, 2026 \u2014 PubMed<\/p>\n
Stages of Sleep:
\nSleep moves through 4 repeating stages; each cycle lasts ~90 min and repeats ~5 times\/night:<\/p>\n
1. Very light sleep: ~1\u20137 min; easily awakened.
\n2. Light sleep: heart rate and breathing slow; ~45\u201355% of total sleep. ~20 min initially, then longer.
\n3. Deep sleep: ~30 min; mainly early in the night; important for physical recovery.
\n4. REM sleep: ~10 min initially, becoming longer (30\u201360 min) toward morning; dreaming supports memory, learning & emotional processing<\/p>\n
Early night \u2192 more deep sleep | Late night \u2192 more REM.<\/p>\n
* 95,559 participants: a watch-like wrist device estimated sleep duration, stages, and nighttime awakenings for 7 days; follow-up 8.9 years.
\n* Sleep quality is more than duration: sleep stages, regularity, and awakenings were associated with future disease risk.
\n* More REM sleep: lower risk of 83 diseases, including HF, AF, dementia, Alzheimer\u2019s and parkinsonism.
\n* More deep sleep: lower risk of 7 conditions, including diabetes and major depression.
\n* Sleep duration: 6\u20138 h\/night was associated with the lowest risk for most relevant condition
\n* Short sleep: <6 h\/night was linked to higher risk several diseases, including HF and DM ; <5 h showed the broadest adverse associations.
\n* Irregular\/fragmented sleep: linked to higher risk of disorders including psychiatric and other disorders.<\/p>\n