Sleep is a hot commodity for nearly everyone. There’s never enough time to get the proper amount of it, and Philadelphia 76ers forward Tobias Harris sees it as the looming problem in the NBA. Via ESPN:

"I think in a couple years," he says, "[sleep deprivation] will be an issue that's talked about, like the NFL with concussions."

Despite the league changing around its scheduling procedures, players still aren’t getting the proper amount of sleep and it may be taking a toll on their performance, injury rate and long-term health. ESPN’s Baxter Holmes detailed the issue in a feature out Monday.

Why are NBA players lacking sleep?

Dr. Charles Czeisler, the director of sleep medicine at Boston's Brigham and Women's Hospital and Harvard Medical School, said professional athletes are not immune from the public health problem of insufficient sleep. He told ESPN that players he’s talked to sleep on average five hours a night, and some “very famous” ones have told him it’s more like three to four hours for them. With a pre-game nap, it’s approximately six hours of sleep per 24-hour cycle. But naps don’t allow the brain to fully cycle through the stages of sleep and it is not as good as overnight sleep.

Young adults ages 18 to 25 and adults ages 26 to 64 are recommended to get seven to nine hours of sleep a night, per the National Sleep Foundation. The foundation recommends having a strict sleep schedule (for example, always go to bed at 10:30 p.m. and wake at 6:30 a.m.), but it’s impossible for NBA players to do that.

Tobias Harris thinks sleep deprivation will become a huge issue in the NBA. (Photo by Michael Reaves/Getty Images) More

NBA schedule a damaging form of ‘shift work’

Timothy Royer is a neurologist specializing in attention disorders, sleep management, stress and anxiety. He joined the Orlando Magic in 2012 as a consultant and began traveling with the team. It’s when he noticed the inherent struggles in the schedule and travel responsibilities, per ESPN.

He views the NBA players’ schedules as a form of shift work, per ESPN, that goes beyond the struggle of working a graveyard/overnight shift a few nights a week. Unlike people who can stay on a daily schedule for the most part around their shifts, NBA players can’t stick to a regimented daily schedule due to vastly different tip-off times. Going across time zones constantly makes it even worse.

"There's not a factory on the planet," Royer told ESPN, "that would move shift workers the way we move NBA players."

The time zone travel throws off circadian rhythms, the natural, internal 24-hour process that determines sleep and awake cycles. The World Health Organization’s International Agency for Research on Cancer classified shift work with circadian disruption as a probable human carcinogen. It impacts mainly emergency medical workers, military personnel, law enforcement and pilots. Studies found the casual link between shift work and cancer is biologically plausible, but more work is needed.

Basketball is also unlike almost all other professional sports. Baseball players almost always play games at 7 p.m. local time, with a few afternoon games. When they travel time zones, they stay in one spot for two to three days. In the NFL, there is one game a week and the rest of the week is almost always spent at home where they can settle into a schedule.

New England Patriots quarterback Tom Brady credited a good start to more sleep, thanks to Sunday afternoon games they’re not typically afforded.

Lack of sleep impacts testosterone, injuries

Royer and his team tested testosterone levels and found vast reductions over the course of a season. In the study, which is not a double-blind, peer reviewed one per ESPN, testosterone levels dropped 64 percent in five months. They found similar results in employees who travel with the organization, leading them to believe it isn’t about playing too much.