Both insufficient & excessive sleep, as well as irregular sleep patterns, are associated with higher risks of cardiovascular & other health conditions. This article explains that sleeping around 7 hours a night & maintaining a consistent sleep schedule is key to reducing health risks & mortality.

While some doctors wake up at the same time every day 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.

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.[2]

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.”[3] 

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.[3]

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.[1]

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.[4] Scores range from 0 (perfectly regular sleep) to 100 (completely random sleep timing).

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 behaviours, such as physical activity and meals. This unstable timing of both stimuli and behaviours leads to disruption of circadian rhythms, with downstream negative health effects.”[4]

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.

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.[5] 

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 behavioural therapy and, in some cases, medication, can be the difference between life and death.[6]

Disclaimer: This story is contributed by Anastasia Climan and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.