Sleep Duration and Longevity

Can your sleep habits impact your longevity? Research has shown that if you sleep too much or not enough, your risk of death increases significantly. This could be a result of the impact of sleep itself on overall health or it could be because other diseases impact both longevity and sleep duration.

Sleep Duration and Mortality - The Study

In one study, researchers followed over 21,000 twins for more than 22 years. They asked questions about the twins' sleep habits and looked at their longevity. Twins make great research subjects because most of them grew up in the same environment and the have the same (or similar) genetic make-ups. This way researchers can isolate the impact of a behavior (say, sleep duration) to an outcome (like longevity). However, in this study, researchers decided to pool the twin data together - this lost some of the benefit of using twins as a study group. It is not clear why they did this, probably something to do with the way the data was collected.

The participants were asked questions at the beginning of the study and 22 years later. The questions concerned sleep duration, use of sleep medications, and quality of sleep. Researchers were also able to collect data on each participant about their longevity.

The Results - Sleep Duration Linked to Longevity

What the researchers found was that if people slept less than 7 hours a night or more than 8 hours a night, they had an increased risk of death. For short sleep women, that increase was 21% (men: 26%) and for long sleeping women, the increase was 17% (men: 24%). If the participants reported using sleep medications, their risk for death also increased. Women using them had a 39% increase in risk while men had a 31% increase.

Over the course of the study, 30% of the participants changed their sleep habits. The most common change was to shift from stable sleep to short or long sleep. These shifts were also linked to increased risk of mortality.

But What Does It Mean?

The increased risk for different sleep durations may be a cause of more or less sleep, but it may also be true that an underlying factor could cause both changes in sleep and changes in risk. For example, if someone had heart disease, that illness could change how someone sleeps as well as change their risk for death. In short, sleep is at least an indicator (there are others too) of overall health. Changes in sleep or unexplained short/long sleep duration should be taken seriously.

More on Sleep and Health

_Source:

Christer Hublin, MD, PhD; Markku Partinen, MD, PhD; Markku Koskenvuo, MD, PhD; Jaakko Kaprio, MD, PhD. Sleep and Mortality: A Population-Based 22-Year Follow-Up Study. Journal SLEEP. Vol 30. No. 10. 1245-1253.