A new analysis of National Football League (NFL) results suggests that the body’s natural circadian timing gives a performance advantage to West Coast teams when they play East Coast teams at night.
“Over the past 40 years, even after accounting for the quality of the teams, West Coast NFL teams have had a significant athletic performance advantage over East Coast teams when playing games starting after 8 pm Eastern time,” says lead author and board-certified sleep medicine physician Dr Roger S. Smith, in a release. “Both the power and the persistent nature of this sleep-related athletic advantage were surprising.”
The study by Harvard and Stanford researchers analyzed all NFL games from 1970 to 2011 that started after 8 pm EST and involved East Coast versus West Coast teams. There were 106 games that met inclusion criteria. An additional 293 daytime games involving the same match-ups were analyzed as a control group.
Data analysis showed a strong advantage for West Coast teams even after adjusting for the Las Vegas point spread, which takes into account factors such as the quality of the teams, injuries, and home-field advantage. During night games, the West Coast teams beat the point spread in 66% of the games and did so by an average of 5.26 points. For daytime games, there was no significant advantage for West or East Coast teams.
“This study is a reminder that the body has an intricate timing system that regulates both sleep and aspects of human performance,” says American Academy of Sleep Medicine President Dr M. Safwan Badr. “We function best when we maintain a daily routine that promotes healthy sleep, which is critical for daytime alertness, performance, and public safety.”
The results are published in the December issue of the journal Sleep.
