Circadian Rhythms & Athletics . . . NFL Odds

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STANFORD, CA - More and more scientists are learning about our bodies' biologic rhythms. What are biologic rhythms? In essence, they are the rhythms of life. All forms of life on earth, including our bodies, respond rhythmically to the regular cycles of the sun, moon, and seasons.

For example, as night turns into day, vital body functions, including heart rate and blood pressure, speed up in anticipation of increased physical activity. These and other predictable fluctuations in body function, taking place during specific time cycles, are our biologic rhythms. They are regulated by "biologic clock" mechanisms located in the brain.

Although biologic rhythms can be "reprogramrned" by environmental influences (such as when a person regularly works the night shift and sleeps during the day), they are genetically "hard-wired" into our cells, tissues, and organs.

Medical scientists who study the body rhythms (chronobiologists) have found that these rhythms can affect the severity of disease symptoms, diagnostic test results and even the body's response to drug therapy. (For more information, please read the Body Rhythms article.)

Among the various biologic rhythm cycles that medical chronobiologists study, the 24-hour day/night-activity/rest cycle is considered a key chronobiologic factor in medical diagnosis and treatment. The circadian rhythm (also referred to as the "body clock") is influenced by a specific area of the brain called the hypothalamus.

Why is the 24-hour body clock so important? Because so many of our normal body functions follow daily patterns of speeding up and slowing down, intensifying and diminishing, in alignment with circadian rhythm. It is now known that the symptoms of many chronic disorders also depend in part upon the circadian rhythms, including asthma, allergies, rheumatoid arthritis, blood pressure elevations (hypertension), and the chest pain of heart disease (angina).

A study from Standford University's

/" rel="dt" onclick="wmdTrack('embd-lnk');">Sleep Disorders Clinic looked at the National Football League's (NFL's ) Monday Night Football results for possible advantages of West Coast versus East Coast teams by a circadian rhythm effect.

The fascinating results, which reviewed the past 25 years of Monday Nite Football games (which always begin at 9:00 p.m. Eastern Standard Time), were published in the journal Sleep (1997;20[5]:362-365). Dr. Roger S. Smith and colleagues at Stanford found that West Coast teams win substantially more often and by significantly more points per game than East Coast teams.

West Coast teams won 63.5% of games, while East Coast teams won only 36.5% of games. West Coast teams won by an average of 14.7 points per game, whereas East Coast teams won by an average of 9.0 points per game. West Coast teams won 59.3% of the home games through the years, while winning 71.0% of Monday Nite Football games. East Coast teams won 56.5% of their home games, but only 43.8% of Monday Nite Football home games!

Overall, West Coast team records are 4.4 percentage points better than East Coast team records since 1970. However, when West Coast teams play East Coast teams for Monday Nite Football, West Coast team records are 27.0 percentage points better than East Coast team records!

Furthermore, West Coast teams performed significantly better than East Coast even when taking into account the statistical predicted point spread by Las Vegas odds makers!

These results, the authors feel, are not a result of jet lag, since this effect should be virtually equal or to the advantage of an East Coast team traveling westward.

The authors concluded that the power of circadian rhythms produces an advantage for the West Coast NFL teams during Monday Nite Football. This advantage they suspect may relate to the fact that West Coast teams are competing closer to the time that they typically train each day. This effect not only enhances home-field advantage for the West Coast teams, but also eliminates the beneficial effects of home-field advantage for East Coast teams!

The findings of this study seem to indicate that athletic performance is enhanced at certain times of day, likely a result of an effect of the body's circadian rhythm. It also implies that "it may be more advantageous to perform closer to one's peak performance time of day rather than try to acclimate to an opponents time zone."

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Reviewed on 8/3/1998

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