One-third of U.S. adults nap on a typical day, according to a new survey from the Pew Research Center.
Naps are more common among men than women, and more common among the poor than the rich.
Naps can be good for you. A study last year in the journal Nature Neuroscience found a 90-minute daytime nap helped test subjects remember things better.
And naps are natural. Humans are bi-phasic sleepers, experts say, which means we're meant to sleep in bouts, not long stretches.
The new survey of 1,488 adults was released this week.
Some 38 percent of men and 31 percent of women surveyed said they had taken a nap in the past 24 hours. Older adults nod off during the day more frequently, especially men. Among those over 50, 41 percent of men nap, while just 28 percent of women do.
Among people making more than $100,000, 33 percent said they nap regularly, while 42 percent of those making less than $30,000 clock out during the day. The income group that naps least? Those who make $75,000 to $99,000 (21 percent).
The Pew analysts say people who report trouble sleeping at night are more likely to take a daytime nap.