March 13, 2007 — Athletes in non-endurance sports, such as swimming and short track running, may improve their times if they compete at 11 PM, suggests a new study that found peak performance often occurs late at night.
The study, recently published in the Journal of Applied Physiology, found that everyone has an athletic circadian rhythm, which is controlled by the hypothalamus at the back of the brain and cycles every 24 hours. That natural rhythm helps drive the behaviors and metabolic changes behind physical performance.
While this research pinpointed the peak performance time, other studies have suggested the body is more generally primed for sports in the afternoon and evening.
"No one really knows why most components of athletic performance peak in the afternoon/early evening," lead author Christopher Kline told Discovery News.
"It seems likely that, since the majority of behavioral and physiological rhythms that could enhance performance peak in the afternoon," added Kline, a researcher in the Department of Exercise Science at the University of South Carolina, "it is the confluence of these rhythms peaking that drives the athletic performance rhythm."
Interestingly enough, most of the 25 swimmers who participated in the study initially reported that they performed best in the morning hours. The researchers, however, suspected other cycles, such as those related to sleeping, eating and daylight, mask a person's true athletic circadian rhythm.
To eliminate these "masking factors," the swimmers adhered to a 180-minute sleep/wake schedule that consisted of one hour of sleep in darkness and two hours of wakefulness in dim light over a 50-55 hour trial period.
Meals were included in the awake times, as were breaks. The participants also performed 200-meter swims scheduled regularly throughout the trial period.
The average difference between best to worst performance for the swimmers was 5.84 seconds, which may not seem like much, but in professional sports, can mean the difference between winning a gold medal at the Olympics and going home empty-handed. First and third place for females competing in the 200-meter freestyle at the 2004 Olympics were separated by just .42 seconds.
Given the study's findings, Kline now urges athletes to be aware of their circadian system and to make adjustments for travel over multiple time zones.
