BRINGING SCIENCE TO TREATMENT

The importance of sleep in performance and injury recovery

Runners sleep before competing in the 2016 New York City Marathon, 2016. REUTERS/Eduardo Munoz 

March madness culminated in the NCAA men’s championship finals when Texas Tech met the University of Virginia. With both schools given the chance to win their first basketball championship, the Raiders of Texas Tech were celebrating what has been for them a comeback season. To what did they attribute their success? Sleep!

After a three-game loss on the road, the senior captain Norense Odiase suggested that the team bag up their phones the night before their next game and get some shut-eye. With some encouragement from the coaching staff, the ban was extended to all nights on the road, not just those before a game. Lo and behold, this little ritual began a winning streak, save one game, that led right to the championship finals.

Was this a superstitious habit or is the team on to something? It turns out the science backs them up. Long known to improve cognitive performance, sleep also impacts both physical and mental health(1). Cognitive function affects memory, including the muscle memory needed for athletes to learn new skills and increase proficiency in current sports techniques. Overall health and wellbeing influence an athlete’s ability to tolerate increased training and performance loads(2). Therefore, sleep plays a role in an athlete’s ability to perform, and resist and recover from injury.

Getting your zzzzz’s

Unfortunately, despite sleep’s importance, athletes are at high risk for sleep deprivation. Student-athletes are particularly vulnerable, with high-school aged athletes generally getting two fewer hours of sleep than their non-athlete counterparts(1). Most student-athletes find the recommendations from the American Academy of Sleep Medicine’s guidelines suggesting that teens 13 to 18 years-of-age get eight to 10 hours of sleep nightly, simply unrealistic. Early morning practice sessions interrupt the circadian rhythm of adolescent sleepers whose natural wake time is mid-morning. Late evening games mean that athletes need more time to wind down and become drowsy at bedtime. In addition, sports performance later in the evening means increased liquid consumption that may require nighttime trips to the restroom, which further interrupts sleep. The time needed for academic work may also delay bedtimes, as academic achievement is often seen as a priority over sleep.

Adult athletes who train before and after work or school also suffer from the same issues. A meta-analysis conducted at Deakin University found that most athletes get seven hours or less of total sleep per night during training or the night of competition(3). Interestingly, in what may be too little too late, athletes seem to make the extra effort on the night before a competition, getting at least seven or more hours of sleep. The researchers found that increases in training load greater than 25% often results in a decrease in total sleep, at a time when the body needs to sleep the most. This may be due to increased levels of cortisol and stress hormones as the body copes with the increased load. When the stress hormones are high it may take longer for the athlete to wind down for bed. Other factors that influence an athlete’s sleep are varied sleep environments when on the road, travel to competitions in other time zones, daily caffeine consumption, and blue light from electronic devices.

Besides external behavioral factors, athletes may also have internal factors that prevent them from getting a good night’s rest. Large athletes, such as American football players, may suffer from obstructive sleep apnea. Other athletes may have baseline anxiety or depression that affects their ability to get to sleep.

Sleep, injury, and recovery

Sports injury typically occurs due to an acute event or the inability to tolerate an increase in training loads. These injuries happen to an alarming number of adolescent athletes, with up to two million high school athletes suffering from sports injury each year(1). Teens who sleep less than eight hours per night are 1.7 times more likely to suffer a sports injury than those who get a full night’s sleep(1). Young athletes who sleep less than six hours show higher rates of injuries during competitions, which tend to be more acute(1). Therefore, sleep is a likely contributor to both acute and overuse injuries.

Sleep plays a role in healing from injury as well. Growth hormone, needed for tissue regeneration and repair, is secreted during sleep. Sleeping decreases the need for oxygen and lowers the amount of energy needed for digestion, which allows the body to devote that energy to building the proteins and transporting the free fatty acids needed for healing. Sleep also increases pain tolerance by up to 20% after just four nights of extended sleep(4).

Clinical implications

While physical therapists aren’t sleeping specialists, an athlete’s sleep clearly impacts healing and rehabilitation outcomes. Therefore, therapists are remiss if they don’t survey a patient’s sleep habits when taking their history. Simple screening questions may help determine if an athlete should be referred to a sleep physician for internal issues, or receive recommendations to modify external behaviors (see table 1). Other considerations for therapy are to avoid early morning PT sessions before school or work and try to schedule later in the day despite the inconvenience. Make a sleep prescription part of your therapeutic plan, especially after a difficult rehab session or during periods when the athlete struggles with pain. Emphasize the importance of sleep with athletes seen for performance training, and maybe they can finally give sports injury a rest.


Table 1: Sleep screening questions

What time do you usually go to bed?
What time do you usually wake up?
How long does it typically take you to fall asleep?
Do you snore?
Do you feel tired during the day?
Do you typically nap during the day?
How much caffeine do you drink per day?
Do you get extra sleep on the weekends?
Do you fall asleep in class or at work?
How long does it take you to wind down after a workout or competition?
What time of day are your practices?
What time of day are your competitions?

While these screening questions aren’t part of a standardized questionnaire, they should give the clinician some idea of the athlete’s sleep history and current sleep status. Answers to these questions may prompt further discussion, recommendations for behavioral modifications, and possibly referral to a sleep physician.


References

  1. Ped Ann. 2017;46(3):e106-e111
  2. Br J Sports Med. 2019;53:513-22
  3. Stand J Med Sci Sports. 2017 Mar;27(3):266-274
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