Health: Feel Sleep Deprived?

By Stephanie Stahl

PHILADELPHIA (CBS) -- Many Americans struggle with feeling tired, needing a nap.  One researcher says something that may happen during a nap could be a clue to whether you're actually sleep deprived.  3 On Your Side Health Reporter Stephanie Stahl explains.

In a bed or on a bench, even on the subway you can see people taking a snooze.

Research shows there are clear benefits to some quick shut eye.

"It can help you compensate for a lifestyle of reduced sleep at night, not getting enough sleep at night.  Make your alertness better.  It can improve your memory," said David Dinges, a Sleep Researcher at the University of Pennsylvania's Perelman School of Medicine.  He says naps can also be counterproductive, people should be strategic.

"You have to understand that you're taking a dose of sleep.  You have to think about it the way you might consume a dose of food, and then you don't want to overeat and you don't want to under eat," said Dinges.  He says the ideal time for nap is generally between 1 and 4 pm.  Napping later can interfere with nighttime sleep.  He says for a quick boost of alertness 10 to 20 minute power naps work best.

And to help with memory 60 minutes of snoozing may do more good.  The downside, a longer nap can leave you groggy.

"It can take as much as 20, 30 minutes to overcome.  It's best to get light on you and move around and take a shower or drink coffee to overcome it," said Dinges.

Naps can help you re-charge, but they can also be an indication that you're sleep deprived.  We spoke with Stanford University Sleep Experts Dr. Rafael Pelayo.

"When you take a short nap, normally you should not be dreaming.  If you're dreaming during a nap that means you're not getting enough sleep overall," said Dr. Pelayo.

Experts say it doesn't matter where you nap, but to avoid a deep sleep it's best to sit slightly upright.  And for people with sleep conditions, like insomnia or sleep apnea, napping isn't recommended.