After getting five hours of sleep, senior Abby Reese woke up at 5:30 a.m. to go to the fitness center and lift weights during her swim season.

“I’m a distance swimmer, [and] sometimes at practices … my muscles will just feel overly heavy and fatigued for no reason if I don’t get enough sleep before a difficult workout,” Reese said.

According to Dr. Joyce Lee-Iannotti, director of the Banner Sleep Center at the University of Arizona, getting the right amount of sleep allows the body to repair strained muscles and organs like the heart.

“There’s also been studies looking at cognitive function, reaction time, overall mood, and those athletes who have impeccable sleep hygiene and are getting good sleep have decreased injury, increased performance time, etc.,” Lee-Iannotti said.

According to Natalia David, a clinical health psychologist who specializes in sleep, the best time to exercise is closer to when a person wakes up because the body is at “full battery”with a full night of sleep.

“The research about the most optimal time to exercise is a bit mixed,” said David. “But it does lean towards morning workouts as being more optimal, but that’s with the caveat of you having had a good night’s rest.”

According to Lee-Iannotti, research is currently being conducted with devices like Apple Watches, which track total amount of sleep without error, to accurately measure the effect of sleep on athletic performance.

“A lot of studies show that when you sleep well, it allows your cells and tissue to repair after exerting [yourself] for such a long period of time,” said Lee-Iannotti. “It also prevents illness in addition to injury, even concussions and traumatic brain injury in contact sports.”

According to Reese, after not getting enough sleep, it is much harder to perform well during sports.

“I had a meet against Deerfield this year, and I didn’t really get that much sleep the night before,” said Reese. “And I feel like my time was probably four or five seconds slower than I would have liked it to be.”