New Brunswick

Best nap? 10 minutes — and drink some coffee first, scientist says

Feeling a little tired? Would a nap help? Maybe, but not if it's longer than 25 minutes, says Michael Edwards of Science East in Fredericton.

Once you get in a deep sleep, it takes time for the grogginess to subside

Sleep intertia can take about a half an hour to wear off after you wake up from a deep sleep, research suggests. (wavebreakmedia/Shutterstock )

It's been a week since clocks went back an hour, but if you're still adjusting to the new schedule, you're not alone, says Michael Edwards of Science East in Fredericton.

"Even shifting the clocks by just an hour is enough to cause all kinds of bad things, like people being tired, not at their best — even connected to more car accidents and things like that," he said in an interview with Shift NB.

But if you're thinking about taking a nap, the shorter the better, he said.

If you really want to be rejuvenated, drink a cup of coffee, then have a 10-minute nap. Since it takes about half an hour for the caffeine to take effect, you can nap while you wait, Edwards said.

'Double whammy'

"You feel refreshed from that and then the coffee kicks in. Double whammy."

Edwards said the key to napping is not to get to the deep sleep stage, or rapid eye movement sleep.

Research suggests if you sleep for more than 25 minutes, you risk falling into the REM state. And when you wake up, you have sleep inertia, where "you're still kind of asleep and a lit bit kind of spacey."

It takes about half and hour for sleep inertia to wear off, Edwards said.

"If you're not willing to obey the 25-minute rule, then you pretty much have to commit to about an hour and a half. Because that puts you through the deep sleep cycle."