SATURDAY, Sept. 10 (HealthDay News) -- Many U.S. college students aren't getting the recommended seven to eight hours of sleep per night, a problem that could affect their ability to learn, a new survey says.

University of Cincinnati researchers asked nearly 200 undergraduate college students aged 18 to 24 who did not live at home about their sleep habits. Most of them worked full- or part-time, and only 24 percent said they got at least seven to eight hours of sleep. More than half (55 percent) said they slept less than seven hours, and 21 percent slept more than eight hours.

Lack of sleep can impair concentration and memory, the lead researcher said.

"Sleep helps us save energy. It repairs cells in the body. And it's key for memory consolidation," study author Adam Knowlden, a doctoral student in the health promotion and education program, said in a university news release.

"During sleep, the brain acts like a hard drive on a computer. It goes in and cleans up memories and makes connections stronger, and it gets rid of things it doesn't need," he explained.

"So if a student is sleep deprived, it affects the whole process. Students aren't able to learn, they're not able to remember, it's harder to concentrate and it affects mood. They're working their way through college and they're not maximizing their learning potential."

Financial concerns and poor time and stress management were among the factors college students said hindered their ability to get enough sleep.

More information

The U.S. Centers for Disease Control and Prevention has more about college health and safety.