According to expert working in the area of sleep, the more hours adults spend commuting and doing their job, the less time they spend sleeping. adults who tend to sleep four and a half hours or fewer also work an average of 93 minutes more on weekdays and 118 minutes more on weekends than people who sleep an average amount. And those who sleep 11 and a half hours or more work an average of 143 minutes less on weekdays and 71 minutes less on weekends. The University of Pennsylvania researchers, who suggest that adults sleep between seven and eight hours each night, believe that time spent at work may in fact have the strongest bearing on how much sleep a person gets. The researchers also found that increased TV-watching time was associated with more sleep.