Does short or long sleep raise death risk in older adults?

Partly. Older adults who had insomnia and also slept under 6 hours had a 25% (men) to 38% (women) higher risk of death, and women who slept more than 8 hours had a 31% higher risk. Short sleep without insomnia, and insomnia with a normal amount of sleep, carried no added risk.

This study looked at 2,844 men with an average age of 76 and 2,967 women with an average age of 83. The men were followed for about 12 years and the women for almost 6 years. Sleep time was measured with actigraphy, a wrist device that tracks movement to estimate how long you actually sleep. That matters, because how long people think they sleep and how long they really sleep are often different.

The researchers sorted people into sleep groups. “Insomnia” meant trouble falling or staying asleep, or taking sleep medicine at least 3 times a week. Short sleep meant under 6 hours on the wrist device. Long sleep meant more than 8 hours. The comparison group had no insomnia and slept 6 to 8 hours. Those groups set up the main question: which sleep patterns track with a shorter life?

What the data show

After accounting for age and other basic traits, men with insomnia plus short sleep had about a 25% higher risk of death (hazard ratio 1.25). The true increase is very likely somewhere between 9% and 43%. Women in the same group had about a 38% higher risk (hazard ratio 1.38), very likely between 12% and 70%.

That link did not hold up once the researchers also accounted for chronic diseases. In both men and women, it was no longer statistically significant. In other words, much of the extra risk may be explained by illnesses these people already had.

Long sleep told a different story in women. Before any adjustment, sleeping over 8 hours was tied to higher death risk in both sexes. But only in women did it stay linked after adjusting for both background traits and chronic disease: about a 31% higher risk (hazard ratio 1.31), very likely between 8% and 60%. People who had insomnia but slept 6 to 8 hours, and people who slept under 6 hours without any insomnia, had no higher death risk than normal sleepers.

Dr. Kumar’s Take

The useful point here is that insomnia complaints and short sleep are not dangerous on their own. The risk showed up when the two came together: a person who feels they sleep badly and who, on a measuring device, really does sleep under 6 hours. That is a more specific warning sign than either one alone.

The fact that the link faded after accounting for chronic disease cuts both ways. Poor sleep might be a marker of illness rather than the cause of early death. Or poor sleep might help drive those illnesses in the first place. This study cannot tell which.

Long sleep in older women deserves more attention than it gets. In this group, it was the one pattern that stayed linked to death even after accounting for chronic disease. Long sleep can signal an underlying problem worth looking into.

How strong is the evidence?

This was an observational study, so it shows links, not cause and effect. The strength is the objective sleep measurement in several thousand people followed for years. The weakness is that the people were quite old, and the women were followed for a much shorter time than the men.

The results also depend heavily on how the models were adjusted. The insomnia plus short sleep link was clear in one model and gone in the next. That is a sign that chronic disease is tangled up with sleep in ways a single study cannot unwind. The authors say future work should test whether improving sleep actually lowers death risk in older people.

Practical Takeaways

If you are older and have trouble sleeping, it may help to track your actual sleep time with a wearable, since the risk in this study showed up only when insomnia came with truly short sleep.
A night of 6 to 8 hours was the reference point, and people with insomnia who still got that much sleep had no higher death risk.
Regularly sleeping more than 8 hours, especially for older women, is worth raising with your doctor as a possible sign of an underlying health problem.
Since chronic diseases appeared to explain much of the risk, keeping those conditions well managed matters alongside better sleep.

FAQs

How much sleep do older adults need?

In this study, 6 to 8 hours measured on a wrist device served as normal sleep, and it was the reference group everyone else was compared against. Needs vary from person to person. Many older adults find their sleep becomes lighter and more broken with age, which is common. What matters more than a single bad night is the pattern over weeks and months.

Is it bad to sleep more than 8 hours as you get older?

Not always, but it can be a clue. Long sleep is often a sign that something else is going on, such as an illness, low mood, or a medication side effect. In this study, older women who slept more than 8 hours had higher death risk even after accounting for chronic diseases. If long sleep is new for you, or you still feel tired after it, bring it up with your doctor.

Can a smartwatch or fitness tracker measure sleep accurately?

The researchers used actigraphy, a research-grade wrist device that estimates sleep from movement. Consumer trackers use a similar idea, and while they are less exact than research devices, they can help show whether “I barely sleep” is really under 6 hours or closer to 7. That gap mattered a lot in this study.

Bottom Line

In older adults, insomnia paired with truly short sleep, under 6 hours on a wrist device, was linked to a 25% to 38% higher risk of death, though chronic disease seemed to explain much of that link. Insomnia with normal sleep time, and short sleep without insomnia, carried no extra risk. In older women, sleeping more than 8 hours stayed tied to a 31% higher death risk even after full adjustment. Both patterns are worth taking seriously as warning signs.

Read the full study