Putting aside time in the early afternoon to nap appears to help older adults compensate for the sleeping problems that tend to occur with age, new research shows.

U.S. investigators found that people between the ages of 55 and 85 who had the opportunity to nap between 2 p.m. and 4 p.m. performed better on tests of mental ability, and had little trouble falling asleep at night.

Nappers got an average of 1 hour more of sleep each day they napped, giving them more than 7 hours - close to the average for young adults, the team reports in the Journal of the American Geriatrics Society.

Study author Dr. Scott S. Campbell of the Weill Cornell Medical College in White Plains, New York explained that napping likely doesn’t interfere with nighttime sleep because it is a “fundamental” part of our sleeping habits.

“There is a biological tendency to sleep in the middle of the day, just as there is to sleep at night,” he said. “So, our brains and bodies have evolved to accommodate both types of sleep, without negatively affecting the other.”

He recommended napping from 30 to 120 minutes in the early afternoon, choosing a dark, comfortable room, and not letting the nap go past 5 or 6 in the evening.

As people age, getting a good night’s sleep can become increasingly more difficult. On average, younger people sleep one hour longer each night than older adults, and research shows that, as people age, they report feeling sleepier during the day and being less alert.

Indeed, almost one-half of people 65 or older say they regularly struggle to get a good night’s sleep, typically because older adults’ sleep is more “fragmented,” Campbell told Reuters Health, meaning they have more trouble staying asleep.

Research in young adults shows that napping can improve daytime alertness, but some sleep advocates have cautioned that sleeping during the day may disrupt nighttime sleeping even further.

To investigate, Campbell and his team asked 16 men and 16 women to either take a nap or stay awake and engage in quiet activities such as reading or watching television from 2 p.m. to 4 p.m. each day for three days. The researchers tested participants’ alertness after napping in a series of mental exercises, and monitored their sleep the night after napping or quiet activities.

All study participants slept during their napping opportunity, averaging 81 minutes of sleep.

Campbell and his team discovered that people who napped slept just as well the night after as they did after the quiet activities. The night after napping, people took an average of 6 minutes longer to fall asleep.]

In addition, after napping people performed better during tests of mental acuity, both that day and the day after, suggesting that the benefits of napping can carry over past the day of the nap.

SOURCE: Journal of the American Geriatrics Society, January 2005.