How many hours of shuteye is best? Here's what the latest science says about sleep

With the release of two studies that try to untangle the relationship between sleep and brain health, specialists are offering some reassurance for anyone who's feeling anxious about optimizing their shuteye.

New research published Monday suggests that getting less than the recommended seven or eight hours of sleep each night might not be as harmful as expected for some people's brains. 

That follows a study printed last week that suggests daytime napping could have some positive effects. 

But sleep science is still a relatively new field, with much more research still to be done on how sleep patterns intersect with human health, according to a range of Canadian experts who weren't involved in the two new studies. 

The evidence so far suggests that sleep needs can be very different for different people, said Dr. Elliott Lee, a sleep specialist at The Royal, Ottawa's mental health centre.

"If you find your sleep pattern to be good for you, then I think that's all right," he told CBC News.

That's a view shared by Dr. ​​Ram Randhawa, a psychiatrist with the University of British Columbia's sleep disorders program.

"My best advice is don't worry. … Step back from all of this news; stop being so fixated on sleep performance," he told CBC News. 

"Don't judge your sleep based on some measure of what the perfect or ideal sleep should be. Everyone's different."

Chronically poor sleep can have serious consequences for physical and mental health, according to Dr. Michael Mak, a sleep medicine specialist at the Centre for Addiction and Mental Health in Toronto. It's been associated with cardiovascular problems, high blood pressure, high cholesterol, obesity, depression and anxiety.

What exactly constitutes good sleep habits is still up for debate. Growing interest in the benefits of a healthy snooze has fed a booming industry, offering everything from wearable tech that tracks your hours of sleep or soothes you with soft vibrations, to weighted blankets and bed cooling systems. 

Napping is something that sleep doctors traditionally advised against for their patients, the specialists consulted for this story said. The thinking was that sleeping during the day contributes to problems patients had sleeping at night.

But, Mak said, "there is no one-size-fits-all rule as it pertains to napping." 

A June 19 paper in the journal Sleep Health suggests a modest link between a larger brain volume and people who reported napping regularly. The volume of a person's brain tends to decline with age, and faster shrinkage has been associated with memory problems and dementia.