CAMBRIGE, Mass. – Want to get the best performance from employees – consider making space for a nap room. A recent Harvard study finds that work performance improves with short power naps. In the study, subjects were asked to spot bars on a computer screen. They worked for four one-hour periods, and researchers noticed that when asked to work continuously, subjects' skills worsened. According to study author Robert Strickgold, an afternoon snooze helps fight information overload and reduces the effects of "burnout" and increases work performance. Sleep experts agree and say that many Americans are sleep deprived. A 2002 National Sleep Foundation poll reports that a quarter of Americans, 47 million, said they didn't receive the minimum sleep requirement of seven to nine hours each night. Nearly two in five of the respondents said lack of sleep affected their daily work and activities. According to a NSF study sleepy employees cost businesses $18 billion in lost productivity. To be effective naps should be kept short – between 15 and 30 minutes -any longer leaves nappers feeling groggy and disoriented. Some businesses are even starting to have a designated employee nap room. For example, the Society for Human Resource Management, which studies workplace trends, offers an all-purpose room for 200 employees at its Alexandria office. The room is a private area where employees can nap or just have time alone.