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The benefits of good sleep come into particular focus for athletes. Post-exercise recovery with extra sleep accelerates the building of muscle, strength, and endurance. Without proper sleep, athletes suffer from poorer reaction times, longer recovery times, and worsened performance.
Sleep deprivation for one night or two, or the accumulation of sleep debt over time (for example, from getting one less hour of sleep per night), impacts reaction time, attention and focus, and physical recovery for athletes. The body restores itself during sleep, so it is necessary for recovery from intense training. A person who is sufficiently well-rested will not waste any resources on staying awake or straining to stay focused and alert. Thus, their body and their mind can focus solely on their athletic performance.
While mild sleep deprivation does not negatively affect aerobic capacity, it does affect reaction time.
Even small amounts of fatigue can significantly reduce reaction time and degrade athletic performance. A 2000 study showed that pulling an all-nighter has a similar effect on reaction time as having a blood alcohol level of .05% – either scenario can cut reaction times by half.
This reduction in reaction time does not affect just performance and play; it also puts the athlete at greater risk of injury. A 2014 study in the Clinical Journal of Sports Medicine found that adolescents who played a game following a night of fewer than 8 hours of sleep were nearly twice as likely to get injured.
Lack of sleep lengthens an athlete’s immediate recovery time, but has detrimental long-term effects as well. In fact, if sleep issues are not addressed, they have the power to cut an athlete’s career short. In 2013, a study published in the American Academy of Sleep Medicine followed 80 Major League Baseball players over a period of three seasons. Their sleeping habits were recorded before the start of the 2010 season and ranked according to the Epworth sleepiness scale. Players who scored high for sleepiness were less than 40 percent likely to still be playing three seasons later, as compared with 72 percent of players who scored low on sleepiness.
The effects of sleep deprivation are not isolated to physical performance. Lack of sleep also impacts an athlete’s mental focus, mood, and stress levels.
Anyone involved in endurance sports understands the power of a positive mindset. High performance athletes and Olympians frequently attribute part of their success to a strong visualization practice and positive attitude. Sleep deprivation has a strong impact on mood and can cause irritability that interferes with an athlete’s ability to think positive and “keep their head in the game.”
Studies indicate that sleep deprivation is linked to increased levels of cortisol, the stress hormone. Athletic performance already causes undue amounts of stress – adding to it is anything but helpful. Competitive athletes often have sleep onset insomnia before an important event, due to nervousness.
In Major League Baseball, “strike-zone judgment” or “plate discipline” refers to a player’s tendency to swing at pitches outside the strike zone. One might expect that over the course of a season, a player’s judgment would improve, since they have more practice, games, and at-bat time under the belt. However, one study of 30 teams found that players showed worse judgment at the end of the season due to mental fatigue from a long season filled with lots of travel.
Sleep deprivation has also been shown to inhibit production of glycogen and carbohydrates. These provide a critical source of energy during sustained athletic activity such as high-intensity weight-lifting or endurance events like marathons. If these stores are depleted, athletes will have less natural energy to rely on. As a result, they may rely increasingly on supplements that can have unexpected side effects.
These studies establish the importance of getting a quality night’s sleep if an athlete wishes to avoid risking athletic performance. The question then, is, does more sleep lead to better athletic performance? Some researchers say yes.
Research shows that athletic performance improves with sufficient sleep. Rested athletes are faster, more accurate, and have a quicker reaction time.
Stanford University’s Sleep Disorders Clinic and Research Laboratory has studied athletes from basketball, track and field, tennis, golf, and cross country. The evidence, usually based on small sample sizes, suggests more sleep results in improved physical performance.
In all of these studies, forcing the athletes undergoing heavy training to sleep longer than average people led to significant improvements in athletic performance.
Trainers recognize the benefits of sufficient and even long sleep for athletes in heavy training. The recommended amount of sleep for an average adult is 7 to 9 hours per night. By contrast, adult athletes should get 10 hours in the weeks surrounding their training and competitive events, to ensure optimal performance as well as an efficient recovery. Adolescent athletes should aim for at least 9 hours.
If it’s not possible to get the full amount of sleep, naps can be a way to “make up” for the missed time, although they are far from an ideal solution. Naps should be kept to 30 minutes or less, and should be avoided before practice or competition as they can cause sleepiness upon waking.
Sleep is important for everyone, but especially for athletes. Sleep allows the body to recover from the physical stresses of the day, as well as process new information and commit it to memory.
During non-REM sleep, the body experiences higher activity levels of cell division and regeneration than while awake. These processes are critical for muscle recovery. Without sufficient nREM sleep, recovery time will be longer.
Sleep spindles are brain waves that characterize stage 2 of light sleep. These brain waves indicate the brain synthesizing new information, such as new training tips, specialized plays or movement, and coaching advice.
During deep sleep, the body regulates levels of cortisol, the stress hormone. When cortisol levels reach higher than normal, it impacts the body’s ability to digest glucose at best and lead to coronary heart disease or diabetes at worst. The inability to process glucose for sleep deprived athletes was similar to effects experienced by elderly individuals. Endurance is directly tied to the body’s ability to metabolize and synthesize glucose for later use as fuel during races and events that last beyond 90 minutes.
During REM sleep, the Hippocampus works to transfer recently learned information to the neo-cortex for later recall. This includes all kinds of information, from muscle movements to visual and written information.
Very heavy exercise experienced by world-class athletes shifts the sleep architecture. The REM latency – which is to say the time period after the person goes to sleep before REM starts – is longer, and the sleeper has less REM during the first half of the night than normal.
Athletes who do not get sufficient REM sleep may notice a corresponding decline in performance. This is especially true for sports where detailed information is required to remember a play (such as football) or to orchestrate a movement (such as diving). For top athletes, fractions of seconds or inches can be the difference between winning or losing. It is critical that their bodies react quickly and perform movements as expected.
Women are more prone to sports-related injuries than men. In particular, the most common injuries for women are ankle sprains, rotator cuff injuries, tendonitis, ACL tears, stress fractures in the foot or shinbone, and plantar fasciitis.
This has nothing to do with physical fitness. Rather, Harvard Medical School researchers attribute the higher risk of injury female athletes endure down to basic physiological differences between the sexes. For example, women have higher estrogen levels, looser ligaments, narrower knees, and a wider pelvis. The physical structure of the bones affects how women move. Female athletes can take proactive measures against injury by strengthening their muscles (especially the hamstrings if the sport is correlated with ACL injury), working to land from jumps with their knees farther apart, and using shoe inserts to prevent foot injuries.
Women are also more prone to sleep disorders such as insomnia, which can interfere with their ability to get quality sleep. Fortunately, women have been shown to recover from sleep debt more quickly than men.
Researchers have conjectured that long, heavy sleep impacts athletic performance due to the fact that growth hormones are released during deep sleep and the extra sleep encourages more hormone production. HGH production during deep sleep promotes tissue repair and recovery of the body and muscles, critical for maintaining sustained performance during an athlete’s career. Natural increase of HGH can be promoted by both exercise and sleep. Some top-level athletes attempt to gain a competitive advantage by taking supplements of human growth hormone.
Athletes wishing to improve their quality of sleep may find the following tips useful.
Follow a regular sleep schedule, even on weekends. Reserve the bedroom strictly for bedroom-only activities. Develop a bedtime routine whereby you do the same things every night before bed, as a way of developing the habit of falling asleep.
The optimal bedroom temperature for sleep is in the mid-60 degrees Fahrenheit. Athletes may benefit from an even cooler temperature, since they sweat more during the day and tend to run hot from all the activity.
Avoid caffeine and alcohol intake, especially in the days leading up to an event. Unless prescribed by a doctor, avoid sleep aids and medication as they may interfere with athletic performance.
Sleep is induced and sustained when your body temperature lowers. Avoid elevating body temperature by not exercising right before bed.
Instead, reserve training and high-intensity workouts for the early morning and afternoon so as to energize the body for the day. Ideally, exercise can be paired with sunlight and performed outside to sync up your circadian rhythms.
Athletes also have to counteract the effects of travel and jetlag on their ability to sleep.
Jet lag is harder to overcome when traveling east. Athletes who have to travel less or are traveling west may have a competitive edge over their opponents, simply by virtue of already having acclimated to the time zone. Giving new meaning to the idea of a “home court advantage,” sleep researcher Dr. Christopher Winter has described this phenomenon as a “circadian advantage.”
Athletes should aim to arrive a few days early if possible, to help them adjust to the new time zone.
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