How 2 common sleep habits increase your risk of death
Key Takeaways
The ideal amount of sleep for adults, on average, is 7 hours a night.
People who sleep too much or too little have a higher risk of death.
Evidence suggests consistent sleep habits are even more important than sleep duration.
While some doctors wake up at the same time everyday after a solid 8 hours of sleep, just as many aren’t getting enough of it—falling victim to habitual tossing and turning or long hospital shifts that don’t allow for adequate shut eye, among other reasons.
While you may think catching up on sleep on off days—sleeping in to log as many as 9 hours or more—the surprising truth is that oversleeping has similar health risks to undersleeping.
Research shows a mortality uptick in people on both ends of the sleep duration spectrum.[] But is either group better off?
What’s the right amount of sleep?
Seven hours of sleep is consistently associated with a lower risk of death. Studies on East Asian populations suggest men experience fewer health hazards with slightly less sleep (6 hours) compared with women, and both sexes have the highest mortality when sleeping 10 hours or more. Men who sleep 5 hours or less, or 9 or more hours a night, have a greater chance of dying from heart disease than those sleeping for 7 hours.[]
In these studies, women’s heart disease mortality increased with any amount of sleep under or beyond 6 to 7 hours a night. In addition, death from cancer was more likely for men sleeping 8 to 10 hours a night. Higher cancer deaths were only seen in women who reached the 10-hour sleep duration.[]
NHANES data shows similar results in the US. In an analysis of 25,481 adults, those sleeping 7 hours a night had the lowest cardiovascular and all-cause mortality over 10 years, with “U–shaped associations of sleep duration with all-cause and cardiovascular mortality.”[] The investigators noted that established effects of inadequate sleep on hormones like testosterone, melatonin, leptin, and ghrelin may contribute to metabolic and other changes that promote poor health outcomes. However, it’s not as clear how longer sleep durations contribute to mortality.
The investigators attempted to control for the possibility that an underlying chronic disease is responsible for links between long sleep and dying sooner. They removed datasets from those with preexisting cancer or heart disease and from any participants who died within 1 year of the study.
More research into this association is needed. Perhaps these groups sleep more because they have fragmented sleep, which promotes atherosclerosis. They may also experience more daytime fatigue and lethargy after sleeping too much, leading to unhealthy lifestyle habits.[]
Additional factors to consider
Age has a strong influence on how much sleep people need. So much so that several leading sleep medicine authorities have recommended age-based sleep duration guidelines. In addition, factors like activity level, genetics, and environment may also affect how much sleep is required.[]
Sleep regularity has emerged as a potentially more consequential factor than sleep duration. In a 2023 study, researchers developed a Sleep Regularity Index using data from 60,977 people in the UK Biobank.[] Scores range from 0 (perfectly regular sleep) to 100 (completely random sleep timing).
They determined that participants on the lowest end of the index with consistent sleep schedules had a 20% to 48% reduction in all-cause mortality compared with those on the highest end. The results also showed a 22% to 57% lower rate of cardiometabolic death and a 16% to 39% lower chance of dying from cancer for regular sleepers.
The researchers found that sleep duration was weakly correlated with sleep regularity and wasn’t as strongly predictive of mortality outcomes. The study authors explained, “People with irregular sleep patterns are exposed to irregular patterns of environmental stimuli, including light, and may have irregularly timed behaviors, such as physical activity and meals. This unstable timing of both stimuli and behaviors leads to disruption of circadian rhythms, with downstream negative health effects.”[]
What can you do about it?
Although it’s well supported that too much or little sleep is associated with earlier death, science has yet to uncover which issue is more of a concern. Aside from maintaining an ideal sleep duration averaging 7 hours a night, the benefits of keeping a consistent sleep schedule can’t be overstated.
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Good sleep supports all aspects of health and quality of life, and insomnia and other sleep disorders impact a significant number of adults—both patients and their HCPs.[] In order to establish healthy sleep habits, you can consider the following:
Maintain a consistent sleep/wake schedule 7 days per week
Set an alarm to wake up and a reminder to go to bed on time
Limit alcohol and caffeine—throughout the day but especially in the evening hours
Engage in daily physical activity
Practice meditation and mindfulness
When poor sleep habits are an issue among your patients, referrals for a sleep study may be warranted when lifestyle changes aren’t enough to improve sleep. Patients should be informed that sleep problems aren’t just something they should accept. Seeking treatment through cognitive behavioral therapy and, in some cases, medication, can be the difference between life and death.[]
What this means for you
People who sleep fewer or more than 7 hours a night may be at risk for early death. The same goes for people who don’t sleep on a regular schedule. You can inform patients about the importance of healthy sleep habits and encourage them to address sleep problems before they take a significant toll.