My oldest brother, the intellectual, writer-type of the family, gifted my mother a beautiful piece of calligraphy when I was 19.  Embossed on the canvas were few stanzas of poetry, one of them being:

The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.

The lines come from a well-known work by Robert Frost, Stopping by the Woods on a Snowy Evening.If you have ever done a close reading of poetry, you know that the words are typically full of a deeper meaning, but Robert Frost in 1923, meant the final two lines to be quite literal, not so uncommon from phrases we often hear uttered including, “You snooze, you lose” or “I’ll sleep when I’m dead,”indicating that sleep is less while working longer hours, crossing one more item off the to-do list, cramming in that 30-minute run at the crack of dawn, scheduling those evening drinks, etc.are all more, and more is better and often praised. The need to sleep might be considered an unfortunate circumstance, especially considering the general recommendation for adults is 7-9 hours of quality sleep per night.  That equates to roughly 1/3 of your day, and that time can be quite valuable depending on your individual responsibilities, obligations and desires. What might be even more overwhelming to consider is that the athlete inyou might need closer to 9-10 hours per night to promote recovery and adaptation throughout training cycles and varying intensities of exercise.  Plainly stated, adequate sleep potentially translates into better performance.

During a sleep cycle, we work through several stages. Each stage boasts specific characteristics and body benefits.  It takes 90-120 minutes to travel through a full cycle of sleep. Thus, after a full night’s sleep you will have worked through the sleep cycle 4-5 times, receiving full benefits from each of the shorter-lived stages. If you are not spending adequate time in each sleep stage or working through the entire sleep cycle enough times in one night, performance can be impaired on several levels.

Neurocognitive

• Athletic movements are nothing more than learned skills, thus learning is essential to athletic performance (Watson).  Memories and learned patterns are consolidated and stored during sleep.
• Lack of sleep has been linked to decreased flexible thinking and decision-making ability during athletic events (Rossa, et al).
• Diminished sleep and sleep quality have a negative impact on reaction time and accuracy (Watson), which certainly plays a high role in field sports, archery, shooting, and dart-throwing, but do consider how reaction time, responsiveness, and quick thinking play into the sports of trail and mountain running.
• Poor sleep is related to diminished subjective well-being in areas of fatigue, mood,soreness, depression, and confusion (Watson, et al). It is hard to be motivated to train and compete when you feel down and cranky.

Endurance

• Decreased sleep has been associated with lower pre-exercise muscle glycogen stores (Skein, etal).  Muscle glycogen is an important substrate related to exercise endurance; lower levels could translate into decreased stamina in endurance efforts.
• Sleep deprivation is linked to increased reports of perceived exertion (Fullagar, etal), which may be another side effect of decreased muscle glycogen.  Efforts feel harder resulting in more rapid fatigue and decreased time to exhaustion.
• Growth hormones are necessary for muscle growth and repair. These are released during the later stages of each sleep cycle.  Lack of sleep decreases muscle recovery and increases the rate of neuromuscular fatigue, impairing performance thereafter.

Injury and Illness

• In one study(Milewski et al), subjects who slept less than 8 hours per night were 70% more likely to report an injury compared to their counterparts who slept more than 8 hours per night; although this study was performed on adolescents, it is not the only study of its kind to find that sleep deprivation is related to increased athletic injury.  
• Individuals that sleep less than 7 hours per night are 3 times more likely to develop an infection (Cohen, et al). Additional studies indicate that illness risk continues to increase as sleep rates decline from 7 hours to 4-5 hours.
• Injury and illness impair ability to train adequately. Without adequate training, your athletic performance goals will surely suffer.

Athletes typically pay very close attention to areas of nutrition, hydration, physical training/conditioning, mental preparation and equipping themselves with all the right gear to achieve these, but sleep often is overlooked, even seen as a waste of time especially in our over-stimulated, over-scheduled lives. While I do not believe nutrition, hydration, physical training/conditioning, and mental preparation are unimportant, I am suggesting that sleep should be another highly regarded contributing factor to athlete readiness, and it inserts itself into other areas of preparation in a unique way.  A small sleep deficit can very quicklycompound to the point that the effects become quite detrimental.  If you snooze, you might quite literally not lose.

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Cohen S, Doyle WL, AlperCM, et al. Sleep habits and susceptibility to the common cold. Arch. Intern. Med.  2009.
Frost, Robert. Stopping bythe woods on a snowy evening. 1923.
Fullager HH, Skorski S,Duffield R, et al. Sleep and athletic performance: the effects if sleep loss onexercise performance, and physiological and cognitive responses to exercise. Sports Med. 2015.
Milewski MD, Skaggs DL, Bishop GA, et al. Chronic lack of sleep is associated with increasedsports injuries in adolescent athletes. J.Pediatr. Orthop. 2014.
Rossa KR, Smith SS, AllanAC, Sullivan KA. The effects of sleep restriction on executive inhibitorycontrol and affect in young adults. J. Adolesc.Health. 2014.
Skein M, Duffield R, EdgeJ, et al. Intermittent-sprint performance and muscle glycogen after 30 h ofsleep deprivation. Med. Sci. SportsExerc. 2011.
Watson A, Brickerson S,Brooks A, Dunn W. Subjective well-being and training load predict in-seasoninjury and illness risk in female youth soccer players. Br. J. Sports Med. 2016.
Watson A. Sleep andAthletic Performance. Current SportsMedicine Reports. 2017.

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