Sleep duration: both sides of 7 hours

In Yin 2017, compared with 7 hours, long sleep was linked to a bigger rise in the risk of dying, from any cause, than short sleep: 10 hours 32% higher, 4 hours 8% higher.

Read your number

Is my sleep duration good?

Read your usual sleep duration alongside your sleep routine. Yin 2017 found the lowest observed death rate around seven hours, with higher rates on either side. This is a population association, rather than a trial showing that changing to exactly seven hours changes your risk. A consistent sleep and wake time is a practical starting point from the guidance below.

If you're 70 or older

At 70 and older, start with your routine: keep a consistent sleep and wake time, get morning light, and keep your bedroom cool, dark and quiet. Treat seven hours as the comparison used by this page. If you are managing a diagnosed condition, work with your clinician on guidance that fits you, as explained in the medical disclaimer.

Try your numbers in the free calculator Choose a practical next step

Evidence already on this page: Yin et al. 2017.

Where you stand

Yin 2017 is the study behind those two numbers. The long side of the curve is steeper than the short side, which is the opposite of what most people assume. How regular the sleep is sits on a different page, and is not part of this score.

Risk is lowest near 7 hours. Shorter sleep is linked to slightly higher risk, and longer sleep to noticeably higher risk.

At 6.0 hours1.01×a typical 45-year-old’s risk, about the same as typical.

See the same numbers as a table

Sleep and risk of death from any cause, as a multiple of a typical 45-year-old’s risk
Hours of sleep a night	Risk vs typical	In words
4.0 hours	1.08×	a little higher than typical
6.0 hours	1.01×	about the same as typical
7.0 hours	1.00×	about the same as typical
8.0 hours	1.04×	a little higher than typical
10.0 hours	1.32×	higher than typical

Risk of death from any cause, with every other marker held at typical. Drag the marker or use the arrow keys. Nothing you move here is saved.

Hatched areas are beyond the studies. The line there is the model’s estimate, or flat.

Source: Yin et al. 2017, Journal of the American Heart Association (PMID 28889101)

The study, not the score

long sleep (≥9 h)

Ungvari et al. 2025 · a different study from the one the score uses

1.34 (1.26–1.42)

34% higher all-cause mortality

The bar shows the study’s 95% confidence interval, the range of values consistent with its data. The tick is the study’s best single figure. The centre line is no difference. The chart above is the score’s own curve, not this study. The score’s main study reports its 10-hour figure in text only, so it can’t be plotted here; this row is the long-sleep interval we do hold.

What it is

Typical hours of sleep in a night. Both less than 7 hours and more than 7 hours are associated with a higher risk of dying. Seven hours is the low point. Yin’s review used questionnaires and interviews to measure sleep duration; a phone or watch estimate can differ from those study measurements.

How the score uses it

Technical notes

The curve is Yin 2017 (generally healthy adults, nadir ≈7 h). Duration is U-shaped: short and long both raise all-cause mortality, so the forest plot shows the categorical pair, not a single HR. Regularity is the stronger all-cause mortality predictor in the same construct family (Windred 2024) — see Sleep Regularity. Both sides now use Yin’s Table 2 directly (40 all-cause mortality risk estimates, not the 57-report extreme-categorical pooling): long side 8 / 9 / 10 h = RR 1.04 / 1.15 / 1.32; short side 6 / 5 / 4 h = 1.01 / 1.04 / 1.08 — changed 2026-09-26 from a steeper linear 1.06-per-hour extrapolation (1.06 / 1.12 / 1.19). Main source: Yin. Supporting: Ungvari 2025 (79-cohort categorical short 1.14 / long 1.34 vs 7–8 h, not a dose–response) / Kwok 2018 (30-study dose–response, no significant increase below 7 h) / Cappuccio 2010 (old 1.12 / 1.30 categorical pairing, not the curve and not a sleep-extension trial). smooth curve interiors are constructed.

How to improve it

Keep a consistent sleep and wake time
Get morning light; dim screens in the evening
Keep the bedroom cool, dark and quiet

What the studies found

Endpoint	Grade	Finding
All-cause mortality	B	7 h = 1.0 (Yin 2017) Technical notes Nadir ≈7 h. Table 2 long side: 8 h RR 1.04, 9 h 1.15, 10 h 1.32. That is 40 all-cause mortality risk estimates, not the 57-report shortest/longest pooling.
—	METHOD	Short side is Table 2, both sides (changed 2026-09-26) Technical notes Curve 4 / 5 / 6 h = 1.08 / 1.04 / 1.01, Yin’s own Table 2 nonlinear estimate — previously a steeper linear extrapolation (1.19 / 1.12 / 1.06). Kwok 2018 found no significant increase below 7 h; Shen 2016 put 4 h at RR 1.07, close to Table 2.
All-cause mortality	C	Short/Long Categorical, Not the Curve (Ungvari 2025) Technical notes 79-cohort pooling (search to Oct 2024): short sleep (<7 h vs 7–8 h) all-cause mortality HR 1.14 (1.10–1.18); long sleep (≥9 h) HR 1.34 (1.26–1.42). Categorical, not a dose-response — this calculator uses Yin’s curve instead. Note: the first author is editor-in-chief of the publishing journal.
Nighttime sleep vs all-cause mortality	B	1.55 at 11 Hours, Nighttime Only (Shen 2016) Technical notes Pooling 35 articles (146,830 deaths across 1,526,609 people), nighttime sleep vs a 7 h reference: 4 h carried all-cause mortality RR 1.07 (1.03–1.13), 6 h was flat at 1.01, and 11 h rose to 1.55 (1.47–1.63). The 24-hour-sleep column in the same paper is different and higher at 11 h (RR 1.84) — nighttime and 24-hour totals are not interchangeable.
All-cause mortality, women only	B	Short Sleep Only Significant in Women (Liu 2016) Technical notes Flexible non-linear meta-regression of 40 cohorts (2,200,425 people, 271,507 deaths): 24-hour sleep of 4 h carried all-cause mortality RR 1.05 (1.02–1.07) and 11 h carried RR 1.38 (1.33–1.44) versus 7 h. In sex-stratified analysis the short-sleep mortality signal held for women but was not significant for men.
All-cause mortality	C	The Original 1.12 / 1.30 Pair (Cappuccio 2010) Technical notes Foundational categorical pooling of 16 studies / 27 cohorts (1,382,999 people, 112,566 deaths), not a dose-response curve: short sleep carried all-cause mortality RR 1.12 (1.06–1.18) and long sleep RR 1.30 (1.22–1.38) versus the reference band — the pair this page used to lead with, before Yin’s finer-grained curve became the curve.

What argues against this

Kwok et al. 2018 (74-study review; dose-response analysis of 30 studies, >1 million people) found no significant increase in all-cause mortality below 7 hours of sleep — undercutting the short-side rise this calculator takes from Yin 2017 Table 2 (4/5/6h HR 1.08/1.04/1.01) even though that side is already the paper's flatter, non-extrapolated estimate. Kwok's long side sits close to Yin's Table 2, so the disagreement is confined to whether short sleep carries any real mortality penalty at all.

Last reviewed 12 October 2026

Sources

6 cited

Yin et al. (2017) — Journal of the American Heart Association
Relationship of Sleep Duration With All-Cause Mortality and Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies
View source
Ungvari et al. (2025) — GeroScience
Imbalanced sleep increases mortality risk by 14–34%: a meta-analysis
View source
Kwok et al. (2018) — Journal of the American Heart Association
Self-Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose-Response Meta-Analysis
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Shen et al. (2016) — Scientific Reports
Nighttime sleep duration, 24-hour sleep duration and risk of all-cause mortality among adults: a meta-analysis of prospective cohort studies
View source
Liu et al. (2016) — Sleep Medicine Reviews
Sleep duration and risk of all-cause mortality: A flexible, non-linear, meta-regression of 40 prospective cohort studies
View source
Cappuccio et al. (2010) — Sleep
Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies
View source

See how sleep duration fits your full score

See how it fits the 8-metric index in the calculator.

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Educational content only — not medical advice, diagnosis, or treatment. Not a medical device; not FDA evaluated. Consult a qualified healthcare professional about your own health, and call emergency services for urgent symptoms. Full medical disclaimer →