title: The impact of circadian misalignment on athletic performance in professional football players.
abstract: OBJECTIVE
  We hypothesized that professional football teams would perform better than anticipated during games occurring close to their circadian peak in performance.
  
  
  METHODS
  We reviewed the past 40 years of evening and daytime professional football games between west coast and east coast United States teams. In order to account for known factors influencing football game outcomes we compared the results to the point spread which addresses all significant differences between opposing teams for sports betting purposes. One sample t-tests, Wilcoxon signed ranked tests, and linear regression were performed. Comparison to day game data was included as a control.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  N/A.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  The results were strongly in favor of the west coast teams during evening games against east coast teams, with the west coast teams beating the point spread about twice as often (t = 3.95, P < 0.0001) as east coast teams. For similar daytime game match-ups, we observed no such advantage.
  
  
  CONCLUSIONS
  Sleep and circadian physiology have profound effects on human function including the performance of elite athletes. Professional football players playing close to the circadian peak in performance demonstrate a significant athletic advantage over those who are playing at other times. Application of this knowledge is likely to enhance human performance.
authors.affiliation: Brigham and Women's Hospital Sleep Disorders Program, Harvard Medical School, Boston MA.
authors.forename: Roger S
authors.initials: RS
authors.lastname: Smith
authors.forename: Bradley
authors.initials: B
authors.lastname: Efron
authors.forename: Cheri D
authors.initials: CD
authors.lastname: Mah
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
mesh_terms: D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005538:Football / Q000502:physiology*; D006801:Humans; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States
keywords: Circadian rhythm; athlete; football; performance; sleep