Jet lag can adversely affect Major League Baseball players: study

A new study has found the jet lag that goes with a grinding schedule of Major League Baseball games that takes players from coast to coast and back again can take its toll on performance. 

Our circadian rhythm regulates our bodies in every way including mentally and physically. It's very close to being on a 24-hour cycle and responds mainly to light and dark cues. When we travel to another time zone, we disrupt our body's natural cycle. How we feel — tired at the wrong times, etc. — is in response to that. We refer to it as jet lag. It can take time for our bodies to readjust.

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Jet lag has been studied widely in athletics, but researchers from Northwestern University in Illinois wanted to determine what aspects of performance were affected, and how. 

Co-author of the study, Ravi Allada, said that MLB games presented a unique opportunity to study the effects of jet lag in a real setting: there are 162 games in a season; the games span four time zones; and there are numerous statistics for almost every aspect of play. 

We all should be mindful of jet lag on our own health and biology.- Ravi Allada, Northwestern University

The researchers collected data from 1992 to 2011, and analyzed the performance stats from 46,535 games.

Home-field disadvantage

The study suggests jet lag does have an effect on specific areas of a player's performance.

"Probably our first major result was the finding that pitchers seemed to be most susceptible to jet lag in the way in which they give up many more home runs," Allada told CBC News.

"And this effect seemed to be large enough to largely negate the home-field advantage."

More surprising to the researchers was how the offence of the home team was affected: if the players were jet-lagged going home, they had fewer doubles, fewer triples and fewer stolen bases and hit into more double plays. The same effect was negligible on the away team.

"Intuitively, we normally think about being jet-lagged when we're away from home; we don't think as much about being jet-lagged when we've returned," Allada said. "And this study would suggest homecomings should be the times when we should be more mindful of the negative effects of jet lag. Certainly baseball teams should be more mindful of it."

East vs. west

Allada said that a way to negate the effects of jet lag — one that some teams may already be doing — is to send a starting pitcher to a city a few days ahead, since they typically have days between games. 

Going east is worse than going west, Allada said.

That's because our circadian cycle isn't exactly 24 hours; it's just a bit slower. So if we travel east and our days start earlier, our internal clocks are thrown off. When we travel west, however, it's a bit easier for our bodies to adjust.

Allada said that the study examined statistics, not individual players, but that it might be interesting to look at individuals to see how some people cope better than others. Also, studying travel between time zones that are farther apart might show more changes in performance. 

Of course, the findings of the study aren't just important for baseball teams; it's important for everyone to take time to readjust when travelling.

"We all should be mindful of jet lag on our own health and biology," Allada said.