Ask an NFL player how many hours of sleep he gets a night, and there’s no telling what the answer will be.
“Maybe four or five,” says Jets cornerback Darrelle Revis.
“At least seven,” Giants quarterback Eli Manning says. “Try to get 8.”
“I really don’t count,” says Ravens linebacker Daryl Smith.
In a game that often comes down to inches, NFL players go to great lengths to find a winning edge. They spend thousands of dollars on offseason training regimens; they follow strict diets that cut out sugar or gluten or load hundreds of grams of protein a day; some even purchase at-home hyperbaric oxygen chambers to help them recover from injuries faster. But as for the free, endlessly renewable and always accessible resource of sleep, NFL players are just like everyone else: They know more is better, but not everyone follows through.
A good night’s sleep is directly tied to key factors such as reaction time, mental alertness, muscular recovery and converting what you’ve recently learned into memory. That’s why the science of slumber has become one of the hottest trends in the NFL: Teams are no longer leaving it to chance that their multimillion dollar investments will manage sleep cycles all on their own.
The Dolphins and Patriots have dark rooms at their practice facilities so players can take naps. Eagles players fill out a morning questionnaire on their tablets, self-reporting how long and how well they slept the previous night. When linebacker Demario Davis arrives at Jets headquarters at 6 a.m. to study film, he does so in the glow of a team-issued Litebook, a space-age device that helps him become more alert by emitting a beam of white light that has the same intensity as full daylight.
Based on conversations with players, coaches and executives around the league, The MMQB has learned of at least a dozen teams that have sought to improve sleep in some way. “The impact it can have is probably a little bit underrated,” says Mike Tannenbaum, the Dolphins’ executive VP of football operations. “It’s a force-multiplier.”
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If you run on four hours of sleep a night for a week, it’s the same as drinking a six-pack and then going to work.
That axiom was heard more than once this summer during The MMQB’s tour of NFL training camps. It originated with Charles Czeisler, the doctor who directs the divisions of sleep medicine at Harvard Medical School and Brigham and Women’s Hospital in Boston. Czeisler has advised teams in all four major professional sports leagues, and one of the organizations he visited last year was the Cleveland Browns.
When Browns head coach Mike Pettine got his first coordinator gig, with the Jets in 2009, he would spend a couple nights a week sleeping on a queen-size air mattress in the closet adjacent to Rex Ryan’s office, getting only three to four hours a night. On game days, he says he often found himself “in a fog” while trying to call plays. Knowing that the impact of missed sleep was even more deleterious for players, he invited Czeisler to talk with his Browns team.
Czeisler tries to distill his message into facts that will resonate with players—thus the six-pack analogy. Another: A week of getting four hours of sleep per night causes your testosterone levels to temporarily dip by an amount equivalent to 11 years of aging. He finds that rookies in the room, alarmed that their bodies might start functioning like those of their graying teammates, immediately take note.
Washington team physician Anthony Casolaro makes a similar sleep presentation every year during training camp. Jim Maas, the retired Cornell professor who coined the term “power nap” a few decades ago, has been advising the Jets on sleep since Eric Mangini was the coach. Based on sleep questionnaires Maas has done with players on multiple teams, he estimates that NFL players average a little more than six hours per night—at least a couple hours short of what their bodies need.
“The average athlete probably needs eight to nine hours of sleep, given their physical demands,” Czeisler says, and even more if you can get it. “I wish I could say there’s a shortcut, but if you are going to be a professional athlete, you need to pay careful attention to sleep.”
Czeisler often shows players the results of a 2011 research article by Stanford’s Sleep Clinic, illustrating the effect of increased sleep on the university’s men’s basketball team. While a small sample size, 11 healthy players were asked to extend their nightly sleep to at least 10 hours for a period of five to seven weeks. At the end, the players ran faster sprints, increased their shooting percentage and improved their reaction time by statistically significant margins.
A single all-nighter, or a week spent getting just four hours of sleep a night, can make one’s reaction time nearly three times slower. Janet Mullington, a colleague of Czeisler’s at Harvard Medical School, has co-authored research showing a linear relationship between cumulative hours of missed sleep and lapses in attention, that is, instances in which it takes someone more than a half-second to react—long enough to miss a tackle on the football field.
Human sleep follows a cycle that lasts about 90 minutes. During this time, hormones are released and information-processing takes place to restore the body and mind. The longer we sleep, the more cycles we complete, leading to more restoration.
Early on in a night of sleep, the cycles are dominated by deep, slow-wave sleep. The blood supply to the muscles increases and human growth hormone is naturally released during this phase, allowing the body to grow and repair. New information learned that day, such as skills in practice or strategies in film study, is rehearsed by the mind and organized during this time. As the night goes on, the cycles shift to longer and longer periods of rapid-eye movement sleep. We dream during REM sleep, the phase in which new skills and strategies are integrated with information previously learned, our existing knowledge.
When sleep is cut short, testosterone levels don’t fully replenish, muscles don’t have as much time to build and recover, and the consolidation of new information into long-term memory is cut short. The final quarter of an eight-hour night of sleep, Maas says, is when the cycles include the greatest frequency of sleep spindles, bursts of brain activity in the motor cortex that play a role in forging new muscle memories from that day’s activities.
“So all these players who are actually getting less than six of hours of sleep, which is probably at least one-third of the team, if not half,” Maas says, “they learn some new plays in practice, but it doesn’t become automatic, and come game time it might look as if they had never practiced at all.”
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In Week 4, the Jets traveled to London to play the Dolphins, a trip for which planning began months in advance. The team packed more than 5,000 items, including power outlet adapters, American condiments and, as The New York Times famously reported, their own toilet paper. But there’s one aspect of overseas travel that NFL teams can’t get a jump on: setting players’ circadian rhythms five hours ahead, to Greenwich Mean Time.
The rule of thumb for long-distance travel is that the body needs one day to adjust per time zone crossed. Leaving New Jersey Thursday night, for a game to be played Sunday afternoon in the U.K., meant the Jets needed a shortcut. Six days before the game, Maas gave a 21-minute presentation at the team headquarters in Florham Park, N.J., detailing a sleep protocol that would help the players’ bodies adjust to London more quickly.
Maas told the team about his work during the Sochi Olympics in 2014, when the Canadian men’s hockey team followed his protocol while traversing 10 time zones just 48 hours before the first game of their run to the gold medal. He then gave every Jets player detailed travel cards prescribing a sleep regimen before, during and after their flight to the U.K.
It included general rules that become even more important during a week of overseas travel: No caffeine after 2 p.m.; no alcohol within three hours of bedtime; keep room temperature between 65 and 68 degrees; turn off or cover any blue, green or white lights in the bedroom, no matter how small. Nap for either 30 minutes, arising before you slip into deep sleep, or 90 minutes, after completing a sleep cycle, but never 60 minutes, because waking up in the middle of deep sleep can make you feel sluggish.
Then there was the new-wave technology.
Waiting in each player’s London hotel room was a kit, purchased by the team for around $100, that contained orange-colored glasses for players to wear while using their phones or studying film on tablets late at night; they are designed to block the short-wavelength light emitted from electronic devices that can interfere with sleep by keeping the brain awake. There was also the Litebook, the iPhone-sized device that resets circadian rhythms by waking the body up according to the new time zone with a beam of 10,000-lux white light.
Some players scoffed at first, but most followed instructions, using the Litebooks for one hour each morning while they were London. The device must be propped up less than an arm’s length away, shining on your retinas from an angle so you are never looking directly into the beam. During the ride to the Saturday walkthrough, players set up their Litebooks on the bus tray tables. On Sunday morning, they were set next to the players at breakfast.
“I thought it was odd,” quarterback Ryan Fitzpatrick says. “It was out of the norm and not something I had ever done before. But even if it was going to help just a little bit, why not try it?”
The Jets’ opponent in London, the Dolphins, didn’t employ the same teamwide technology for that trip. But back in South Florida, Miami’s expanded sports-science division has taken measures to harness sleep for performance. There’s an area connected to the weight room with dimmed lights and eight sleep tables set up with electronic relaxation systems. Players put on an eye mask, attach electrodes behind their ears, slide on noise-canceling headphones that play calming acoustics, and lie down.
Quarterback Ryan Tannehill was one of the players who made daily visits to the sleep room during training camp to nap during a break in the afternoon schedule. With these devices, Tannehill says, a 20- to 30-minute nap will feel like you slept for two hours. Players use the room less frequently during the regular season, but the devices can be taken on the team’s charter flights.
Many teams also offer sleep studies to their players. Those with thicker necks, such as linemen, are at risk for sleep apnea, a disorder in which disrupted breathing interrupts your sleep cycles. Casolaro, the team physician in Washington, says he’ll send these players for an overnight study at a nearby hospital so they can be treated. There are also wearable and bedside devices that can track sleep at home. Eli Manning was one of a handful of Giants players who volunteered to have his sleep tracked with a wearable wristband during training camp. This summer, not tasked with learning a new offense, he discovered that he got more sleep than last year. On days when he was a little short of his eight-hour target, Manning would slip into the training room and steal a 30-minute nap.
Tracking sleep can be a tricky issue for teams. Eagles linebacker Connor Barwin wore a wearable sleep tracker during Chip Kelly’s first season in Philadelphia, but he didn’t find that part of the coach’s sports-science initiative to be very accurate—or necessary.
“It was optional if you wanted to do it, but that, I think, was a little intrusive for guys,” he says. Now the Eagles ask players to self-report their sleep instead.
Last month, the NFL Players Association filed a grievance against the league and its 32 teams to cease and desist monitoring players’ sleep without the union’s permission. The collective bargaining agreement allows the NFL to require players to wear tracking devices during games and practices, but not at home; the CBA also stipulates that the league needs to obtain NFLPA consent before using sensors for health and medical purposes. (An NFL spokesman called it a club matter, and said that every use of sleep tracking technology of which the league is aware has occurred with a player’s consent.)
The NFLPA’s primary concern is privacy. Even if players consent to having their sleep tracked, they may not know how the team could use that information. This season, all sensor technology used by clubs for health and medical reasons, such as measuring hydration or core temperature, is subject to a CBA compliance form. Teams must disclose what devices are being used, what data is being collected and where it is stored, and who has access to the information. Sleep, however, is different because it takes place at home. Whether it is considered a performance factor or a health/medical issue, the union doesn’t want players’ employers inside their bedrooms.
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There are plenty of reasons why players fall short of getting enough sleep: having young children, early morning wake-ups that interfere with the natural body clocks of younger players, social lives and the pressures of the job.
Darrelle Revis, who plays cornerback probably better than anyone else in the league, says one of the reasons he gets so few hours a night is because his mind is always racing. “I did look at people like Einstein and JFK, and how they didn’t get a lot of sleep because their mind is just always going,” Revis says. “Certain things, like a pass play, might just pop into my head.”
Browns cornerback Johnson Bademosi, a Stanford alum, once participated in the university’s sleep research for class credit, extending his sleep to 10 hours a night. “It was obvious that sleep helps with everything,” he says, “but it’s hard to get that much. It really does take a lot of discipline, and no extracurricular activity apart from football.”
It’s a commitment that some of the league’s best players have made. Tom Brady does cognitive exercises at night to destimulate his brain so he can fall asleep by 9 p.m., part of the 38-year-old’s regimen to ward off Father Time, as Sports Illustrated reported last year. J.J. Watt, last year’s NFL defensive player of the year, was shown on HBO’s Hard Knocks this summer advising a younger teammate to hit the sack around 8:30 p.m. so he could get 10 hours of sleep. Colts kicker Adam Vinatieri, who in 2014 made 30 out of 31 field goals in his 19th NFL season, says one of the reasons he’s been able to perform well in his 40s is making sure he gets eight hours of quality sleep a night.
Reading about Brady’s routine influenced Falcons quarterback Matt Ryan, who says he never stays up past 10 p.m. during the football season and stopped showing up to work at 5 a.m.
“I thought that showed dedication and work ethic,” Ryan says. “I don’t do that anymore, because I realized it is more important to be rested and ready than it is to beat everybody to work.”
More and more, sleep is the being recognized as the most obvious, accessible and natural performance-enhancer in the NFL—the kind of secret weapon that players have always dreamed about.
Kalyn Kahler contributed reporting for this story.