Sleep Schedule Linked to Dementia Risk, Scientists Warn

Irregular sleep patterns may increase your risk of dementia, scientists have warned.

We've been told before that not getting enough sleep—or getting too much—may increase our risk of developing dementia. But the regularity of this sleep may also play an important role, a new study, published in the journal Neurology, has found.

"Sleep is multifaceted and is involved in several dementia mechanisms," study author Matthew Pase, a professor and dementia researcher at Monash University in Australia, told Newsweek. "Good sleep is essential for maintaining connections in our brain and memory consolidation; we remember information better after a good night's sleep. Sleep also plays a garbage truck-like function in the brain, helping to clear out metabolic waste that accumulates in our brains when we are awake.

"Sleep health recommendations often focus on getting the recommended amount of sleep, which is seven to nine hours a night, but there is less emphasis on maintaining regular sleep schedules."

To investigate the impact of sleep schedule on dementia risk, Pase and his team conducted a study with 88,094 individuals with an average age of 62. Participants were asked to wear a device to track their sleep cycle over a seven-day period. Participants were then followed for an average of seven years. Within that period, 480 individuals had developed dementia. But was this linked to the participants' sleep?

"Sleep regularity is defined as the day-to-day consistency (or regularity) of sleep-wake patterns," Pase said. "We calculated the sleep regularity index as the probability of being in the same state (asleep or awake) at any two given time points, 24 hours apart, averaged over one week. A person who sleeps and wakes at exactly the same times every day would have a score of 100 whereas someone who sleeps and wakes at completely random times would have a score of 0. The average score in our sample was 60 and people with irregular sleep had scores lower than that."

Compared to those with an average sleep regularity index, those with highly irregular sleep schedules were significantly more likely to develop dementia. However, this risk did not decrease for those with very high sleep regularity.

"Based on our findings, people with irregular sleep may only need to improve their sleep regularity to average levels, compared to very high levels, to prevent dementia," Pase said. "Future research is needed to confirm our findings."

While these results do not confirm that irregular sleep causes dementia, they do show an interesting link between sleep habits and the development of this condition.

However, not everyone is able to guarantee a regular sleep schedule every night. "People can have commitments that can get in the way of sleep," Pase said. "[But] there are several other lifestyle variables that are related to dementia risk, meaning that good sleep is only part of the picture.

"For example, looking after your heart health (e.g. blood pressure), being physically activity, maintaining a healthy weight, staying socially connected, quitting smoking, and looking after your mental health may all help to protect the brain in the face of advancing age. Moreover, many of these lifestyle variables are related, meaning that improving on some risk factors may also improve others (e.g., exercising and managing stress may also improve sleep)."

Is there a health issue that's worrying you? Do you have a question about dementia? Let us know via health@newsweek.com. We can ask experts for advice, and your story could be featured on Newsweek.