The Centers for Disease Control and Prevention said Thursday that more than a third of adults in the U.S. get less than 7 hours of sleep each night – and it ends up affecting them during the day.

Adults who were studied said the lack of shut-eye made it difficult to concentrate, remember and drive. The CDC based its statistics on two studies:

• Thirty-five percent of people surveyed in 12 states said they slept less than 7 hours a night, on average

• A national survey found approximately 23 percent of adults had difficulty concentrating because they were tired. Another 18 percent struggled to remember things, and 11 percent had difficulty driving or commuting.

The Associated Press contributed to this report.