For us humans, sleep is completely crucial to proper functioning. As we’ve all experienced, we’re simply not as adept at anything in our lives if we don’t sleep well. Without proper sleep, whether it’s a short-term or long-term deficit, there are substantial effects on mood, mental and cognitive skills, and motor abilities. When it comes to recovery from hard physical efforts, there’s simply no better treatment than sleep, and a lot of it.

Most research on the effects of sleep on athletes has studied sleep deprivation. And those effects are quite strong. Just like the rest of us, athletes see a drop in their performance across all sorts of measurements if they are kept awake for the entire night, or even just interrupted in their sleep.

It seems like certain kinds of athletic tasks are more affected by sleep deprivation. Although one-off efforts and high-intensity exercise see an impact, sustained efforts and aerobic work seem to suffer an even larger setback. Gross motor skills are relatively unaffected, while athletes in events requiring fast reaction times have a particularly hard time when they get less sleep.

But instead of focusing on the effects of a lack of sleep, it’s more interesting to explore additional sleep as an advantage. If an athlete gets more sleep than his or her competitors, will that lead to an edge? That’s just the question that Stanford researcher Cheri D. Mah set out to answer. She reached out to athletes at her university, trying to find a group that would participate in an experiment in which they would first measure their athletic performance after having their normal amount of sleep, and then spend weeks trying to extend their sleep as much as possible, to see what effect it would have on objective measurements of athletic performance. Amazingly, no one had ever done a study to see the effect of sleep extension on competitive athletes.

The Cardinal men’s basketball team volunteered to be Mah’s study cohort. Eleven players used motion-sensing wristbands to determine how long they slept on average—just over 6.5 hours a night. For two weeks, the team kept to their normal schedules, while Mah’s researchers measured their performances on sprint drills, free throws, and three-point shooting. Then, the players were told to try and sleep as much as they could for five to seven weeks, with a goal of 10 hours in bed each night. Their actual time asleep, as measured by the sensors attached to their wrists, went from an average of 6.5 hours to nearly 8.5 hours.

The results were startling. By the end of the extra-sleep period, players had improved their free throw shooting by 11.4 percent and their three-point shooting by 13.7 percent. There was an improvement of 0.7 seconds on the 282-foot sprint drill—every single player on the team was quicker than before the study had started.

A 13-percent performance enhancement is the sort of gain that one associates with drugs or years of training—not simply making sure to get tons of sleep. Mah’s research strongly suggests that most athletes would perform much better with more sleep—if they could get it. But it’s not quite that easy; in fact, athletes face challenges with their sleep that many of us don’t have.

The first challenge that many elite athletes face is the travel demands of their sport. When you’re a pro athlete, you spend a lot of time on the road. If you’re a professional sports team athlete in the U.S., you’re spending your time zigzagging across the country, flying back and forth to meet the demands of schedule-makers who don’t always take the travelers’ circadian rhythms into account.

The mileage can pile up in a hurry, especially for teams on the West Coast, which are farther away from the rest of the teams in their leagues. West Coast teams perennially have to travel more miles than their competition—in 2013, the Seattle Mariners flew more than 52,000 miles while the Chicago White Sox, with their central location and nearby division rivals, only flew about 23,000. Some years, the L.A. Kings have had to fly more than 55,000 miles to reach other teams in the NHL, while the New Jersey Devils were clocking less than 29,000. Bouncing around the country, leaving late, arriving early, having to play the next day—it’s no surprise that travel and the management of sleep is a huge issue for athletes.

To try and deal with this disruption, teams have consulted with sleep researchers like Mah. Most NBA players have adapted by taking a nap in the afternoon, between morning practice and the evening’s game. “If you nap every game day, all those hours add up and it allows you to get through the season better,” NBA all-star Steve Nash told the New York Times. “I want to improve at that, so by the end of the year, I feel better.”

Domestic travel is bad enough, but for athletes in many Olympic sports, there’s a heavy dose of international travel as well. Randy Wilber, at the U.S. Olympic Committee, notes that there’s very little published research on how to deal with jet lag even for people who travel professionally, like pilots, let alone research on how to minimize its effects on elite athletes. “We’ve had to develop those protocols ourselves pretty much from scratch,” he says.

Does traveling a long distance have a demonstrable negative effect on teams? There haven’t been a lot of studies, but Bill Barnwell, of, looked at 15 years of data for the NFL, examining the winning percentage of road teams by the distance they had to travel. Teams who traveled more than 2,000 miles had a winning percentage of 40 percent, while those who traveled less than 1,000 miles won 43 percent of the time.

Bad news for teams like the Oakland Raiders, who had to travel more than 28,000 miles in 2012, while teams like the Indianapolis Colts only traveled 8,494 miles.

And these travel effects seem to accumulate over the course of a season. Researchers at Vanderbilt University examined the plate discipline of hitters in baseball over the course of the season, and found that hitters swing at more pitches outside the strike zone late in the season than they do earlier in the season. Why? Dr. Scott Kutscher, the leader of the research team, said in a press release, “We theorize that this decline is tied to fatigue that develops over the course of the season due to a combination of frequency of travel and paucity of days off.”

Kutscher’s team has found that this decay in plate discipline has become more pronounced in baseball since 2006—the year that Major League Baseball banned stimulants. (For years, bowls of amphetamines, known as “greenies,” were a fixture in baseball clubhouses.) Out of the 30 teams in Major League Baseball, 24 saw this decrease in 2012, the year the study examined. That suggests that if a team can find a way to stem this fatigue effect, they might have a competitive advantage—in fact, it’s already happened. The San Francisco Giants actually improved their plate discipline over the course of the 2012 season, and the team went on to win the World Series.

Perhaps the Giants also improved what researchers call “sleep hygiene”—making sure that your bedtime is as regular as possible, removing the bright digital clock from your bedside table (studies show the light disrupts sleep), finding a comfortable temperature (research shows a cool room is best). Start viewing sleep as a performance booster rather than a chore, and the effort it takes to sleep well will seem like a smart investment.

This article has been excerpted from Mark McClusky's Faster, Higher, Stronger: How Sports Science Is Creating a New Generation of Superathletesand What We Can Learn from Them.