WHEN Cheri Mah talks to NBA players, she'll tell them how poor sleep (or lack thereof) negatively affects on-court performance. She'll mention how chronic inadequate sleep builds "sleep debt" that must be reduced over time.
Mah, a sleep research fellow at the University of California San Francisco Human Performance Center, also brings up another issue: blue light.
It's emitted from televisions, computer screens, tablets, smartphones, and at night, it suppresses the body's attempt to produce melatonin, a hormone that helps induce sleep.
"Most of them are pretty surprised," said Mah, who said she has worked with thousands of collegiate and professional athletes since 2002. "That's really because no one has told them that before and they didn't realize it could potentially impact their sleep."
Researchers say poor sleep leads to reduced reaction time, which in turn can lead to increased injuries. The average reaction time is 250 milliseconds, but it can take three times as long if people stay awake all night, making them as impaired as if they were legally drunk, according to Dr. Charles Czeisler, the director of the Division of Sleep Medicine at Harvard Medical School who has been a consultant for several NBA teams.
In the 2011-12 lockout-shortened NBA season, when teams played at a hectic pace -- back-to-back-to-back sets and, in some cases, nine games in 12 days or 20 in 31 -- the number of one-game injury absences during the first 60 days of play increased 63 percent from the same amount of time the season prior, according to statistics compiled by the league.
Czeisler said sleep is even more vital for younger players, and thus poor sleep is more harmful. One night of lost sleep is 10 times more detrimental to those ages 18-25 than to those 60 and over, Czeisler said, because younger people's sleep is much deeper, more restorative, and the body's "drive" to sleep is more intense.
While Mah said NBA awareness of sleep science has relatively improved in recent years, there's now talk of "blue-light pollution," an issue that Tim DiFrancesco, the Lakers' strength and conditioning coach, said is especially concerning for young players, who are conditioned to stare at a screen at all hours.
"There's plenty of information showing that people are addicted to social media," DiFrancesco said. "They can't not scroll through their Twitter feed. They need it the same way that an alcoholic [does]; if they have a drink sitting there, they're going to have it."
"That's all we know -- that's what we've grown up with, the iPhones, the iPads, the laptops," said Doug McDermott, a Chicago Bulls forward who missed 28 games because of injury after being drafted 11th overall. "They all produce so much light.
"It's easy to say you won't be on your phone before you go to bed, but the reality of it is, all of us 19- to 23-year-old kids who are just starting your NBA career, you're probably not going to listen and you're probably going to be on your phone anyway."
Several players mentioned how difficult the transition is from college to the NBA when it comes to sleep: more games, more late nights and especially more travel.
"In college, you have a schedule because you're not traveling as much, so you can go to bed at 11 or 12 every night," McDermott said, "and now, I can go to sleep at 11 one night and the next night go to bed at 3.
"It's tough. I've learned to sleep when I can."
NBA travel impacts sleep enough, but technology often only makes it worse.
"Family is trying to talk to you about the game, people whose opinions you value are trying to talk to you about your performance - what might have happened or what didn't happen," said Orlando Magic rookie point guard Elfrid Payton, drafted 10th overall in 2014. "You've got to turn your phone off -- that's the only way, I think."
Young NBA players aren't the only ones glued to a screen late at night, of course. In a 2011 poll by the National Sleep Foundation, 95 percent of those surveyed reported that they use some type of electronics (computer, video game, cell phone, etc.) at least a few nights a week within an hour before going to bed.
Mah recommends 7-9 hours of sleep per night for adults and 8-10 for NBA players. With regards to NBA players and blue light, DiFrancesco said, "I would feel confident saying they're easily losing one to two hours of sleep per night -- and it's probably more."
A potential solution is an application called f.lux, which adjusts light on a device's display to the time of day, limiting blue light after sundown. There are also amber-lensed goggles -- known as "blue-light blockers" -- that are designed to be worn at night.
McDermott said veterans have suggested reading a book for 15-20 minutes before bed, and that he uses an app on his phone that sounds like a whirring fan.
"I try to have the same noise to sleep to every night to keep it consistent, because you're sleeping in a million different beds," he said. "You can at least have some sort of consistency if you do something like that."
Dan Pardi, a sleep researcher at Stanford University and at Leiden University in the Netherlands, preaches education most of all.
"Blue light is not the problem," Pardi said. "It's the timing of it. You want a lot of blue light during the day. You don't want it during the night, because you can start to essentially cause the brain to think, oh, it's day, even though it's night, and that will initiate a shift in all the rhythms in your body.
"That's really problematic if you have to be performing the next day as an athlete. You can basically be suffering from a form of jetlag."