Understanding the Impact of Body Clocks on NFL Performance
On Sunday, October 25, the Pittsburgh Steelers and New Orleans Saints face off at Stade de France, kicking off at 2:30 p.m. Paris time. But for the players, the game won’t feel like an afternoon matchup. A Steeler, whose internal clock is still set to Pittsburgh time, will be playing at 9:30 a.m., while a Saint, still on New Orleans time, will experience kickoff as early as 8:30 a.m. Complicating matters further, just hours before the game, clocks in France fall back an hour, illustrating the complex interplay of time zones, body clocks, and athletic performance.
The Body Clock Behind the Box Score
Every player has a circadian rhythm governing various bodily functions, including temperature, alertness, reaction time, and muscle output. Sleep research consistently shows that athletes perform best in the late afternoon and early evening of their internal clock. Importantly, a player’s body clock doesn’t adjust instantaneously when transitioning to new time zones. The conventional understanding in sports science is that it takes approximately a day to adjust for each time zone crossed. This means NFL teams, which typically travel for games on weekends, rarely allow enough time to fully adapt before kickoff.
Additionally, human circadian rhythms run slightly longer than 24 hours, making it easier to adjust when traveling west (where you effectively gain time) than when traveling east (where you lose time). This has been a key finding in research that examines performance with respect to geographical travel in sports.
The Monday Night Pattern
The most notable findings relating body clocks to NFL performance come from classic studies on Monday Night Football (MNF). Researchers from Stanford University, including Roger Smith and Christian Guilleminault, analyzed every MNF game from 1970 to 1994 featuring West Coast teams playing against East Coast teams, all set to kick off at 9:00 p.m. Eastern Time. Their research confirmed a significant pattern: West Coast teams consistently outperformed East Coast teams in these late-night games, winning more often and beating the betting spread on average.
In a follow-up 2013 study, Smith and his colleagues expanded the dataset to include 106 night games from 1970 to 2011, reinforcing earlier findings. West Coast teams beat the spread in 66% of these games by an average of over 5 points. The significance of these findings is not just in win-loss records but in how they highlight the nuanced advantages conferred by body clock synchronization with local game times.
The Overlooked Daytime Games
Interestingly, the same 2013 study found no discernible advantage for either side in daytime games between East and West Coast teams. This counteracts the commonly held belief that West Coast teams struggle during early games, which feels like 10:00 a.m. to them. While individual player performance may still be impacted by this timing, statistically, daytime games haven’t shown the same measurable disadvantage.
Broader League Insights: Baseball and Basketball
The narrative surrounding body clocks isn’t unique to football. Similar patterns have been observed in other major sports like baseball and basketball. Researchers conducted extensive studies to analyze performance effects based on travel and time zone changes.
For instance, a study involving MLB found that home teams showed a notable decline in performance after eastward travels, with pitchers—especially those recently returning from West Coast games—giving up more home runs. Similarly, an NBA study revealed that Pacific teams playing against Eastern teams exhibited improved performance when playing at home compared to when they had to travel east—reinforcing many of the findings seen in football.
The 2026 NFL International Slate: A Body-Clock Challenge
The NFL’s plan for a record nine-game international schedule in 2026 brings these body-clock considerations to the forefront. Many game timings cater to American TV slots, often creating mismatches with players’ internal clocks. For example, games in Europe will often kick off in the morning local time for American teams, which can severely affect performance.
Consider the Steelers and Saints game: the timing not only reflects the clash of time zones but also the unique situation of turning back the clock in France on game day, theoretically giving an advantage to players who have spent the week adjusting to Paris time.
October: A Month of Time Changes
The NFL will also experience unique scheduling quirks in October, particularly on November 1, when Daylight Saving Time ends in the United States. This results in every NFL team gaining an extra hour of sleep, affecting not just player performance, but also strategic considerations for coaches and fantasy managers alike.
For example, the clock change means that the Arizona Cardinals will transition from effectively syncing their game times to Pacific Time to adjusting to Mountain Time. This impacts how they prepare for games scheduled in the Eastern time zone.
Practical Implications for Fans and Analysts
For fans and analysts, understanding these dynamics offers valuable insights for evaluating team performances and approaches leading into games, especially those that require long-distance travel or occur at atypical hours. The strongest documented effects are primarily seen in night games, particularly when West Coast teams are playing against East Coast teams.
While it’s essential to recognize the influence of body clocks in scheduling and performance analysis, it’s equally important not to overstate these effects. Individual games can and often do defy trends, making this an engaging but complex field of study.
In the world of professional sports, where the nuances can make all the difference, the intersection of scheduling, travel, and human biology remains an underappreciated yet fascinating aspect of how games are played and won.