At the annual meeting of the Associated Professional Sleep Societies, a research abstract was presented by Stanford University researchers, who later took the idea and performed an actual research study. Their postulation was that if athletes spent more time sleeping than the usual recommended time of 7-8 hours a night, they might be able to improve their mood, and therefore their performance on the field. The theory had not been researched by exercise physiologists, but their intrigue with the idea led them to try it out. Researchers worked with five members of the women's tennis team at Stanford. The students, who were ages 18 to 21, followed their normal sleeping patterns for a few weeks to start with a clean slate. Then they were asked to sleep for a longer period, with the goal being at least 10 hours a night, for 6 to 7 weeks. Researchers conducted the study during the school's normal tennis season, and the athletic performance and the mood of the subjects were measured and noted following each practice session. Although the athletes didn't always comply with sleeping for 10 hours a night, researchers noticed a difference even if they extended their sleep by as little as 30 minutes. Their drills in sprinting time went faster, they were able to hit the balls more accurately and more deeply, and their overall mood was improved. Scientists also performed the study using members of the men's and women's swimming teams. After getting more sleep, the swimmers were able to increase their speed, react more quickly off the blocks, improve their turn time, and increase their kick strokes. When the study was repeated working with six players on the Stanford University men's basketball team, researchers measured improvements in sprint times, free-throw shooting accuracy, mood, and alertness. Exercise physiologists say that the studies were too small to provide definitive statistics. But the natural hormones released into the brain while a person sleeps aids in physical recovery processes, which strengthens the body. Growth hormone and serotonin are released into the body during sleep, and they both enhance athletes' moods and encourage repair of damaged tissue. Therefore, extra sleep translates to improved moods and facilitated tissue repair. Many athletes accumulate hours of sleep debt by not getting enough hours of sleep every night. This lack of rest can result in detrimental effects on mood, cognitive function, and reaction time. Negative effects such as these can be either lessened or eliminated totally if athletes make sleep a priority, particularly if they increase their sleep time to more than the usually recommended time. Coaches at Stanford have been closely following the involvement of their athletes in the ongoing sleep studies, and they have begun to change their practice and travel schedule to allow athletes to get enough sleep. For most of the coaches and the study participants, they are just now beginning to realize the major impact that sleep can have on individual athletic performance and accomplishments. Scientists believe that although these studies focused specifically on athletes in particular disciplines, the results suggest that all athletes in all sports can benefit greatly from getting extra sleep, in order to develop a competitive edge that will allow them to perform at the highest level possible, while remaining healthy and strong.