Cap a nap at 40 minutes: sleep sitting will automatically rewake you

 17 Apr 2016 - 0:00

Cap a nap at 40 minutes: sleep sitting will automatically rewake you
A daytime nap should be limited to 40 minutes at the most, experts say. (Malte Christians / dpa)

Around two in the afternoon it hits: Your eyes feel heavy and your mind drifts from work to thoughts of a soft bed.

You want to nap. Some say siestas are a waste of time. Others swear by them as a fount of energy. Who's right? 

Ingo Fietze, a doctor of sleep medicine, says it's scientifically proven that naps do bring you fresh energy and wakefulness if you've gone short on sleep the previous night.

But the effect only works for people who have healthy patterns of sleeping and waking, Fietze stresses. 

Adults should aim for seven to eight hours of sleep per night, but if they have clocked only six hours or work shifts, a nap does help.

Another of Fietze’s requirements is that "a nap shouldn’t last longer than 40 minutes." Napping longer leads to deep sleep, also known as REM sleep, and it can take 30 to 60 minutes to fully awaken from REM sleep, he explained.

If these prerequisites are met, an afternoon nap can work wonders. It will leave you refreshed and alert for the next three to four hours, said Fietze who is director of the Center for Sleep Disorders at Charité Hospital in Berlin.

To make sure you don’t sleep past the 40-minute limit, Fietze recommends setting an alarm clock or sleeping upright. People wake up automatically during the 40-minute timeframe if they sleep while sitting, he said.