All humans are biologically programmed to require sleep, as essential as air, food, and water. The demands of sports training and competition make good, regular, and restful sleep even more important. No athlete can ever realize his or her true sport potential unless their sleep is as vigorously pursued as all other aspects of the athletic life.
Sleep deprivation is not one or two nights of inadequate rest. Sleep deprivation is also referred to as a cumulative sleep debt, the product of ingrained sleep habits. Adolescents who normally require over nine hours of sleep per night to accommodate the growth processes ongoing in their bodies will often desire even more sleep if they are participating in sports. Athletic adults of all ages require more sleep than the general requirement for inactive persons of between seven and nine hours of sleep per night.
The physical effects of sleep deprivation have been the subject of considerable scientific study, particularly as the condition might affect shift workers, or doctors and nurses working very long shifts in an environment when an error due to fatigue might have fatal consequences. As a general rule, when a person has remained awake for periods of 24 hours, the ability to perform relatively basic mathematic problem solving and memory skills will diminish by over 20%. Another comparison is the condition of a sleep-deprived person and someone whose motor skills are significantly impaired by the consumption of alcohol; sleep deprivation is similar to a blood alcohol level reading that will support the criminal offense of impaired operation of a motor vehicle in most countries of the world.
The physiological effects of sleep deprivation on athletic performance are profound. They include an impairment of the athlete's motor function. The inability of the athlete to control all aspects of muscular movement will result almost invariably in substandard sports performance. Examples include races such as the hurdles, which depends on the fluid combination of power and the striding over each hurdle, or sports where the athlete must coordinate a series of movements in rapid succession, a drive to the basket in basketball or the pole vault. As a consequence, the risk of injury to the sleep-deprived athlete is significantly greater than normal.
Another effect is an impairment of the athlete's visual reaction time. In sports where the athlete must react to an object, such as a hockey goaltender or a cricket batsman, this impairment will mean the difference between success and failure. Until 2005, major league baseball turned a blind eye to the widespread use by its players of stimulants such as amphetamines. These drugs were a preferred method through which players could combat the sleep deprivation and fatigue caused by back-to-back games and extensive travel, that would otherwise impair reaction time.
Sleep deprivation also causes delays in an athlete's auditory reaction, such as the reaction to a starter's pistol or a teammate calling out information during a game. There is general impairment of an athlete's tactical and decision-making capabilities. As for aerobic performance and endurance, the storage, conversion and metabolism of glucose as an energy source are decreased through sleep deprivation. It is estimated that glucose metabolism will deteriorate in a period of seven to 10 days of limited sleep by as much as 30% to 40%. In addition to the limitations that sleep deprivation will impose on physical performance, this condition will impair the ability of the body to properly store the glycogen necessary to provide the body with reserves to use during vigorous training or competition.
The psychological effects of sleep deprivation on an athlete are as profound as its impacts on the body. A sleep-deprived athlete will often believe he or she is even more fatigued than they actually demonstrate, with all of the usual symptoms of fatigue exaggerated in the mind of the athlete. Absence of sleep will also trigger the endocrine system to produce greater levels of cortisol, the hormone sometime referred to as the stress hormone, an adverse effect on mood. With cortisol, and the other physiological consequences of sleep deprivation, the athlete will often feel irritable and short-tempered.
Overtraining is a well-known athletic condition where an athlete overreaches in the training objectives for a period of time, either through excessive training volume, intensity, or both. If an athlete is deprived of proper sleep, the overtraining syndrome may occur on a much smaller work volume or intensity, because the body's lack of proper sleep reduces the maximum that it can safely endure.
When sleep deprivation has affected an athlete, the remedy is not so simple as one or two good sleeps, although such a development is a start. The athlete must incorporate sleep in properly defined measures into the training program as with any other training component. In typical cases, sleep deprivation can be completely addressed within a few weeks of proper attention.