A 95,000-Person Study Found 69 Diseases Tied To One Sleep Pattern
You know those nights when you check the clock and realize you have five hours before your alarm? Every once in a while, it's probably nothing to worry about. But if five or six hours has become your usual routine, your sleep may deserve a closer look.
In a recent study1 of nearly 95,000 adults, researchers found that how long people slept was connected to their risk of dozens of diseases.
They also looked at what happened during those hours, including how often people woke up during the night (called nighttime wakefulness) and how consistent their sleep was from one night to the next.
About the study
Researchers analyzed sleep data from 95,559 adults in the UK Biobank.
For seven days, participants wore wrist devices that tracked their movement while they slept, giving researchers a more objective picture of their sleep than asking people to estimate how long they slept.
The researchers used this data to estimate total sleep time, time spent in different sleep stages, nighttime wakefulness, and night-to-night changes in sleep duration.
They then tracked participants for a median of 8.9 years and compared these sleep patterns with 1,049 different health outcomes. Because this was an observational study, the findings show links between sleep and health, not proof that one directly causes the other.
One sleep range kept showing up
Researchers found meaningful links between sleep duration and 69 diseases. For most of these conditions, the lowest risk was seen among people who typically slept 6 to 8 hours a night.
That group had lower risk across conditions such as type 2 diabetes, anemia, dementia, and chronic kidney disease. The finding is a little different from the familiar 7-to-9-hour recommendation for adults, but it doesn't mean six hours is a new target for everyone.
Sleep needs vary, and this study didn't test whether changing someone's sleep duration would prevent disease.
The biggest differences appeared among very short sleepers. People getting less than five hours had 37 of the 41 significant health risks identified in the analysis when compared with the six-to-eight-hour group.
These included heart failure, type 2 diabetes, and chronic obstructive pulmonary disease.
Sleeping more than eight hours was linked to fewer of these risks, although it was associated with a higher risk of major depressive disorder.
The quality of your sleep matters, too
The six-to-eight-hour group also had some healthier sleep characteristics.
They had the highest proportion of REM sleep, a stage involved in memory and emotional processing. When researchers looked at REM sleep on its own, more REM was associated with lower risk of 83 diseases across 12 categories, including heart failure, atrial fibrillation, and dementia.
They also had less deep sleep disruption, meaning less time awake after initially falling asleep. More nighttime wakefulness was associated with higher risks of several conditions, including substance dependence and osteoarthritis.
Sleep regularity mattered as well. People whose sleep duration changed more from night to night had higher risks of anxiety and major depressive disorder.
The six-to-eight-hour group had the lowest levels of both nighttime wakefulness and sleep irregularity.
Give your sleep routine a little more structure
You don't need to panic over one late night. But if poor sleep has become your normal, these findings offer a few practical places to start:
- Keep your schedule steady: Try to go to bed and wake up around the same time each day, including on weekends.
- Protect your sleep window: Give yourself enough time to get the amount of sleep your body needs rather than routinely squeezing sleep into the leftovers of your day.
- Look for common disruptors: Late-day caffeine, alcohol, stress, and screens before bed can all interfere with sleep.
- Pay attention to persistent problems: Frequent waking, loud snoring, or feeling exhausted despite spending enough time in bed can be signs of a sleep disorder such as sleep apnea or insomnia. If that's happening regularly, talk with a health professional.
The goal isn't to make every night perfect. It's to create a sleep routine that gives your body a reliable chance to do its overnight work.
The takeaway
Your sleep routine is about more than a number on a tracker.
This study links a steady 6-to-8-hour sleep window, fewer nighttime disruptions, and healthy REM sleep with better long-term health.
