That researcher studied sleep, especially how it affects athletic performance. Stevens was concerned about that area because his Butler Bulldogs were about to return from playing three games in three days in a tournament more than 4,200 miles from home.

So Cheri Mah, who works at the Stanford Sleep Disorders Clinic and Research Laboratory, sent a list of suggestions to help the Bulldogs recover after playing in the event in Maui.

Mah recommended practicing at certain times on certain days while taking others off as the team prepared for its next game less than a week later. The two had spoken before, after she had written a study about sleep and college basketball players.


“She told me it was going to be a little bit of a process and it wasn’t always going to be right,” Stevens said, “but they were fresh and ready to go on Tuesday when we were supposed to be.”

And the Bulldogs won that game — along with the next 12.

Sleep wasn’t the only factor involved, of course, but it is a hidden factor that professional teams are considering after years of disregarding it.

Utilizing sleep isn’t new for the team that Stevens joined this year, though. Since 2009, Dr. Charles Czeisler, the chief of the division of sleep medicine at Brigham and Women’s Hospital and director of sleep medicine at Harvard Medical School, has helped coordinate the Celtics’ travel schedule to give players optimal rest.

Czeisler, who has worked with other NBA teams and is known around the league as the “Sleep Doctor,” started working with the Celtics after giving a presentation to ex-coach Doc Rivers in which he explained how lack of sleep affects, among other things, reaction time and memory retention.


Czeisler has worked with a range of professionals from NASA astronauts to Secret Service agents and he uses scientific studies to back up his claims, some of which include:

■ The average reaction time is 250 milliseconds, but it can increase to 800 or 900 if a person stays awake all night, making them as impaired as if they were legally drunk.

■ One night of lost sleep is 10 times more detrimental to those ages 18-25 than to those 60 and over, because in younger people sleep is much deeper, more restorative and the body’s “drive” to sleep is more intense.

■ Lack of sleep affects the parts of the brain that control emotional reaction and judgment. As such, Czeisler said, sleep-deprived players are much more likely to lose control of their temper and respond emotionally if, say, they don’t like an officiating decision.

■ Sleep helps the brain consolidate memory, especially procedural memory, so if a player learned a new play or a new move that day, Czeisler said, “Amazingly enough, during sleep, the brain will rehearse this move over and over.”

With Czeisler’s instruction, the Celtics focused on creating larger windows for sleep by adjusting practice times and when they’d arrive or depart certain cities. For example, if the team doesn’t play in back-to-back games that force it to fly that night, he suggests it stay in town and leave the following morning. Forward Brandon Bass joined the Celtics in 2011 and said they focused on sleep more than any of his previous three teams (New Orleans, Dallas, Orlando). He added that it’s helped change his view of sleep.


“It’s very important,” he said. “It’s going to wear on you, eventually.”

Earlier this year, Czeisler made a similar presentation to Stevens and said he was “delighted” to find that Stevens was already well-versed on the subject.

“It’s really important,” Stevens said of proper sleep. “It’s in a lot of ways, we all know it, but we don’t all know how it affects us physically. We all think we can get through on minimal sleep. The bottom line is, to be healthy, you need to have a rhythm.”

It can be hard to develop a rhythm in the NBA, given the routines. Night games usually don’t end until after 10 p.m. By the time players shower, dress, speak to the media, and eat dinner, it’s close to midnight. Most don’t fall asleep until well later, either because they’re too wired and/or out on the town. And if the team is traveling, players might not even arrive at the hotel in the next city until 3 a.m.

It’s the equivalent of working a 4 p.m.-midnight shift, and players often face 9 a.m. practices or 10 a.m. shootarounds as well. Czeisler said he learned the reason most teams follow that schedule is because it’s just what they’ve always done. But he also found that most teams considered lack of sleep as something elite athletes should be able to play through.


“It was as if you could just toss players into a plane like a piece of luggage and expect them to perform just as well after flying all night, as if they had actually gotten the sleep they need to perform at their best,” he said.

Several players say they can function on little sleep, but genetically “short sleepers,” as they are known, actually make up about 1 to 3 percent of the population, according to the Wall Street Journal. And out of every 100 people who believe they need only five or six hours of sleep a night, only about five really do, Daniel J. Buysse, a psychiatrist at the University of Pittsburgh Medical Center and a past president of the American Academy of Sleep Medicine, told the Journal.

Mah, who has worked with NBA, NFL, NHL, Olympic, and collegiate athletes, said teams should also consider “sleep debt” — the cumulative effect of sleep loss.

She added that one night of good sleep is not enough to erase, say, a week of poor rest. In fact, she said, it can take weeks to significantly reduce and eliminate sleep debt.

“Just like they focus on their physical training and other types of recovery and nutrition, sleep needs to be something that they prioritize, “ she said.

The optimal amount of sleep for an average person varies, but Mah and Czeisler each said it is around eight hours — though NBA players might need at least nine.

Many NBA players take pregame naps — Miami’s LeBron James and the Lakers’ Kobe Bryant swear by them — and Mah and Czeisler said that naps are a good power boost that can last for a few hours, but naps and caffeine can’t replace a night of proper sleep.


“It won’t turn a couch potato into an NBA player,” Czeisler said, “but if you’re looking for a potential advantage, sleep could mean the difference between winning and losing.”

So it is no surprise that Stevens is interested in this potential advantage, as he is, more than anything, a coach who spends his every waking moment searching for that one edge that could decide the difference.

Baxter Holmes can be reached at baxter.holmes@globe.com. Follow him on Twitter @BaxterHolmes.