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Can Time Zones Decide NFL Games?

A study looks at how circadian cycles affect NFL players
Can Time Zones Decide NFL Games?
Illustration by Tane Williams

The National Football League, with its revenue sharing and salary caps, is obsessed with parity. But it can’t regularize everything—there’s the weather and Bill Belichick. And time zones: A paper from sleep researchers at Harvard Medical School, Stanford University, and the University of California at San Diego finds that football teams from the Pacific time zone have a pronounced advantage at home games when playing teams from the East.

The study, published in the December issue of Sleep, looks at 40 years of West-on-East NFL action, such as the San Francisco 49ers vs. the New York Giants, or the Oakland Raiders vs. the New England Patriots. The data were divided into evening and afternoon games and compared with the Vegas point spread to control for the sort of factors bookies take into account—home-field advantage, injuries, whether a game matters to a team’s playoff chances. In the evening, Pacific teams beat the spread twice as often as their East Coast opponents. “That just one piece of information could be that predictive over 40 years is a powerful piece of knowledge,” says Roger Smith, one of the authors and a clinical instructor at Harvard Medical School.