EvidenceDPreliminaryVery uncertain: animal or cell studies, or studies in people with several serious weaknesses.
Most older adults seem to do best with about 7 to 8 hours a night. Studies linking sleep to health risks are observational Studies that watch what happens to people rather than assigning a treatment. They can show links, not cause and effect., and few focus on people over 65.
Who it's for
Adults over 65 aiming for steady, regular sleep; no group has a clearly proven target.
What to expect
Risks in studies rise with much shorter or longer sleep, not at 7 to 8 hours.
Watch out for
Sleeping 9 hours or more, or long naps, was linked to worse health.
Both short and long sleep carry higher death risk
Each dot is the pooled risk of death with a line showing its likely range; a value of 1 means no difference.
Figure 1. Cross-sectional Associations Between Sleep Duration per Night and z Scores at Baseline A-D, Participants who had a sleep duration of 7 hours per night served as the reference…
Figure 2. Mean Differences in Rate of Change in z Scores During Follow-up A-D, Participants who had a sleep duration of 7 hours per night served as the reference group.
The National Heart, Lung, and Blood Institute says adults should sleep 7 to 9 hours a night2Guideline · 2022How Much Sleep Is Enough?Experts recommend that adults sleep between 7 and 9 hours a night.National Heart, Lung, and Blood Institute (NIH). The American Academy of Sleep Medicine and Sleep Research Society advises 7 or more hours for adults aged 18 to 60, so its advice doesn't directly cover people over 651Guideline · 2015Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research SocietyAdults aged 18 to 60 should sleep 7 or more hours a night on a regular basis to promote optimal health. Regularly sleeping less than 7 hours is associated with weight gain and obesity, diabetes, high blood pressure, heart disease and stroke, depression and a higher risk of death, as well as impaired immune function,…American Academy of Sleep Medicine and Sleep Research Society. The American Heart Association calls for evidence-based sleep recommendations in guidelines6Guideline · 2016Sleep Duration and Quality: Impact on Lifestyle Behaviors and Cardiometabolic Health: A Scientific Statement From the American Heart Association.Sleep duration, mostly short sleep, and sleep disorders have emerged as being related to adverse cardiometabolic risk, including obesity, hypertension, type 2 diabetes mellitus, and cardiovascular disease. Here, we review the evidence relating sleep duration and sleep disorders to cardiometabolic risk and call for…Circulation.
What the studies show
A review that pooled prospective studies in generally healthy adults found the lowest risk of death and heart disease at about 7 hours. Risk rose with both shorter and longer sleep3Meta-analysis · 2017Relationship of Sleep Duration With All-Cause Mortality and Cardiovascular Events: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies.Our findings indicate that both short and long sleep duration is associated with an increased risk of all-cause mortality and cardiovascular events.J Am Heart Assoc. Another review of 16 studies with about 1.4 million people found the same U-shaped pattern, with a larger rise in risk for long sleep than short sleep4Meta-analysis · 2010Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies.Both short and long duration of sleep are significant predictors of death in prospective population studies.Sleep. These figures compare groups, so the gain for one person depends on their starting risk.
A review of 74 studies with over 3.3 million people found sleeping 9 hours or more was linked to higher death risk, rising further at 10 and 11 hours. Under 7 hours showed no clear added risk5Meta-analysis · 2018 · 684 peopleSelf-Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose-Response Meta-Analysis.Conclusions Divergence from the recommended 7 to 8 hours of sleep is associated with a higher risk of mortality and cardiovascular events. Longer duration of sleep may be more associated with adverse outcomes compared with shorter sleep durations.J Am Heart Assoc. Studies disagree on short sleep.
A review of 35 samples (97,264 older adults, 55 and over) linked both short and long sleep to higher odds of poor thinking and memory7Meta-analysis · 2016 · 97,264 peopleSelf-reported sleep duration and cognitive performance in older adults: a systematic review and meta-analysis.Prospective cohort studies revealed the significant long-term impact of short and long sleep on multiple-domain performance only. These findings establish self-reported extreme sleep duration as a risk factor for cognitive aging.Sleep Med. These studies mostly reflect one point in time or self-reported sleep.
In two large cohorts of people 45 or 50 and older, thinking scores declined faster with 4 hours or less or 10 hours or more of sleep than with 7 hours8Meta-analysis · 2020 · 756 peopleAssociation Between Sleep Duration and Cognitive Decline.In this pooled cohort study, an inverted U-shaped association between sleep duration and global cognitive decline was found, indicating that cognitive function should be monitored in individuals with insufficient (≤4 hours per night) or excessive (≥10 hours per night) sleep duration. Future studies are needed to…JAMA Netw Open.
In a study of 11,054 Chinese adults aged 60 and over, followed for two years, naps of an hour or more were linked to higher death risk. Sleep of 6 to 8 hours at night was linked to lower risk. The pattern was U-shaped, and the study can't show cause12Observational study · 2026 · 11,054 peopleNighttime sleep, midday napping, and mortality in Chinese older adults: A China Health and Retirement Longitudinal Study longitudinal cohort study.112). Nighttime sleep of 6-8 h and avoiding daily napping ≥60 min may be associated with a lower risk of mortality; however, as this was an observational study, causal inference cannot be established.J Int Med Res.
In 3,306 Chinese adults, short steady sleep was linked to about half the odds of healthy aging compared with normal steady sleep. Rising sleep time was linked to about two-thirds the odds10Observational study · 2024 · 3,306 peopleThe association between sleep duration trajectories and successful aging: a population-based cohort study.Increasing and short stable trajectories of sleep duration are associated with lower odds of successful aging relative to participants in the normal stable trajectory. The findings underscore the critical importance of monitoring dynamic changes in sleep duration in middle-aged and older Chinese adults.BMC Public Health.
Key studies
Study
Who
What it found
Review of 74 studies, 20185Meta-analysis · 2018 · 684 peopleSelf-Reported Sleep Duration and Quality and Cardiovascular Disease and Mortality: A Dose-Response Meta-Analysis.Conclusions Divergence from the recommended 7 to 8 hours of sleep is associated with a higher risk of mortality and cardiovascular events. Longer duration of sleep may be more associated with adverse outcomes compared with shorter sleep durations.J Am Heart Assoc
3.3 million adults
Sleep over 8 hours linked to higher death risk
Review of 16 studies, 20104Meta-analysis · 2010Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies.Both short and long duration of sleep are significant predictors of death in prospective population studies.Sleep
1.4 million adults
Short and long sleep both linked to higher death risk
Review of 35 samples, 20167Meta-analysis · 2016 · 97,264 peopleSelf-reported sleep duration and cognitive performance in older adults: a systematic review and meta-analysis.Prospective cohort studies revealed the significant long-term impact of short and long sleep on multiple-domain performance only. These findings establish self-reported extreme sleep duration as a risk factor for cognitive aging.Sleep Med
97,264 adults 55+
Short and long sleep linked to poorer thinking
Study following people, 202612Observational study · 2026 · 11,054 peopleNighttime sleep, midday napping, and mortality in Chinese older adults: A China Health and Retirement Longitudinal Study longitudinal cohort study.112). Nighttime sleep of 6-8 h and avoiding daily napping ≥60 min may be associated with a lower risk of mortality; however, as this was an observational study, causal inference cannot be established.J Int Med Res
11,054 Chinese adults 60+
6 to 8 hours lowest risk; long naps linked to higher risk
Safety
Sleeping much more than usual can be a sign of illness, which may explain part of the link to poor health. The guideline notes that longer sleep suits people recovering from sleep debt or illness1Guideline · 2015Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research SocietyAdults aged 18 to 60 should sleep 7 or more hours a night on a regular basis to promote optimal health. Regularly sleeping less than 7 hours is associated with weight gain and obesity, diabetes, high blood pressure, heart disease and stroke, depression and a higher risk of death, as well as impaired immune function,…American Academy of Sleep Medicine and Sleep Research Society.
What we don't know
Whether the best amount differs at 65, 75 or 85, since most studies cover mixed ages or Chinese cohorts only.
Whether changing sleep length changes health, since these studies only observe people.
Written by AI from the studies listed, without review by a clinician, and graded with the GRADE method. It can be wrong, so check the studies it cites. Education, not medical advice.