Traci Watson

Special for USA TODAY

A new study finds that jet lag takes a profound toll on pro baseball teams, especially those playing at home rather than on the road. Pitchers who have recently crossed multiple time zones perform noticeably worse than those who stayed put, and the cumulative damage is not trivial, researchers report in Monday’s Proceedings of the National Academy of Sciences.

The impact “is large enough to essentially negate the home-field advantage,” says study co-author Ravi Allada, a neurobiologist at Northwestern University and a Chicago Cubs fan. He and his colleagues found that jet lag affects both home and away teams, “suggesting it was a real effect, and significant in terms of the size of that effect.”

Athletes have long blamed jet lag for poor performance. World-champion sprinter Maurice Greene, for example, said it contributed to losses in European and Japanese races in the early 2000s. “My body feels asleep,” Greene told reporters.

Baseball players are not immune, as previous research has shown, and Allada and his colleagues wanted to pinpoint the precise skills affected by jet lag. So the researchers examined more than 45,000 major-league games played from 1992 to 2011, using statistical methods to disentangle the effect of jet lag vs. the effect of the reality that “some teams are really good … and other teams are not so good. I won’t name them,” Allada says.

Baserunning aggression - or lack thereof - was an area that particularly jumped out.

The results showed that jet-lagged players running the bases in their home stadiums tended to steal fewer bases and register fewer doubles. Jet lag might erode decision-making, aggressiveness or some other trait involved in a batter’s determination to try to round an extra base, Allada says.

Jet-lagged batters playing at someone else’s stadium, however, didn’t have the same problem. It’s not clear why, but lifestyle may be the culprit. When players fly home, they often return to families and long to-do lists, both potential enemies of sleep.

The most powerful effect of jet lag, though, afflicts home and away teams alike. Jet-lagged pitchers give up more home runs than pitchers who aren’t struggling to adjust to multiple time-zone shifts, the study shows. Either way, teams may want to more strongly consider sending their pitchers to a distant game site early to give them time to adjust, Allada says.

The new analysis is “a stand-out study” for dissecting exactly how jet lag affects performance, says W. Chris Winter, a neurologist in Charlottesville, Va., who works with several sports teams and has written a forthcoming book about sleep problems. The finding that pitching is especially affected makes sense to Winter.

“Throwing a 96-mph fastball exactly where you want is probably the toughest thing going on out there on the field, outside of that batter trying to hit it,” he says.

Teams are already working to minimize the effects of jet lag. And the league is taking notice too: Major League Baseball's new collective bargaining agreement calls for more day games played on so-called getaway days beginning in 2018, allowing players to arrive sooner in their next city.