A new study tracks the effects of jet lag on Major League Baseball players' game performance.
MLB players affected by jet lag
Credit: Michael Ivins/Boston Red Sox/Getty Images

A new study out in the Proceedings of the National Academy of Sciences takes stock of 20 years of travel data from Major League Baseball teams with an intriguing conclusion: Jet lag effects were “largely evident after eastward travel with very limited effects after westward travel.”

So those L.A. to New York red-eyes really could take a toll, as it turns out.

The study considered 46,535 games, from 1992 to 2011, narrowing it down to games in which instances of east-west jet lag of at least two hours would be present for one of the teams—so about 5,000 games qualified.

The results showed that winning percentages dipped for teams that needed to travel east, regardless of whether they were visiting an eastern field or were returning to an eastern home.

On a more granular level, the study also noted that a jet-lagged defense—specifically, pitchers—allowed more home runs.

While we can only guess as to how normal humans stack up against baseball players in prime athletic shape in our resilience to jet lag, this is one more piece of scientific evidence in favor of the understanding that west-east travel goes against the grain of human circadian rhythms.

In the meantime, we can consider scheduling East Coast-bound flights with extra cushion for recovery upon landing.

For the full results, including an in-depth discussion of offensive and defensive disadvantages of jet lag, you can read the study here.