Now that Super Bowl LI is behind us, the calendar turns to America's national pastime: baseball. Major League Baseball players will begin reporting for spring training next week, and the season starts April 2.

For many fans, the game can keep them engaged and rooting for their favorite team late into evening. If the players take the excitement into extra innings — sometimes into the early morning hours — it can make for a tired morning at work the next day.

But this can be doubly so for the baseball players who have a game within a day's time. Sports professionals have long felt that when an athlete has significant disruptions in his daily routine — in particular the circadian rhythms related to activity and rest — that the athlete's performance may suffer.

A recent study in Proceedings of the National Academy of Sciences looked at the performance of MLB players and how the jet lag of traveling from coast to coast impacted performance. The research accounted for differences in home and away performance, travel direction and other team variables.

Ravi Allada, Ph.D., from the Department of Neurobiology at Northwestern University, and his team found that not only did performance suffer, but also that one direction of travel had a greater impact than the opposite direction. When a team traveled from west to east there were significant changes in performance, but when the travel was from east to west, the effect of jet lag was limited.

Researchers found that a major detriment occurred in home team offensive performance when the travel was west to east, and evidence of this was found in the slugging percentage. But the away team's offense did not suffer to the same degree.

Home runs allowed were an expression of the negative effect of jet lag, and the researchers concluded that the result demonstrated a highly specific effect of jet lag induced circadian misalignment. The impact of disrupted circadian function was concluded to be enough to eliminate the home field advantage if a team had traveled from west toward the east.

"One of the more surprising things we found was that in some cases we would see effects on home teams and not away teams," Allada reported. "We don't typically think of home teams as suffering jet lag, but that's what we observed."

Home team advantage for baseball exists, but it is less than in other sports such as football, basketball or soccer. One reason being that individual performance is more critical in baseball than other sports, and the precise interactions relying on group performance may further enhance home team advantage in the other sports.

Individual performance at all levels of play, as well as team play, may be impacted with circadian disruptions and jet lag.

While the circadian influences of jet travel on athletic performance have been recognized, the study was the first to identify areas of specific play that are affected in baseball. Allada and his colleagues had looked at 20 years of Major League Baseball data from 1992 and 2011. The researchers evaluated 46,535 games and further analyzed 4,919 of these games where players had crossed two time zones. They then looked at offensive statistics and defensive statistics.

Aspects of study included home runs allowed, stolen bases and sacrifice flies. They compared the numbers on different teams that had traveled west to east with those traveling east to west. The research observed that home teams had a less aggressive offense after having traveled west to east. With the reduced responsiveness, the players were less likely to attempt doubles, triples, stolen bases and other plays that require bolder and aggressive base running.

Jet lag and disruptions in circadian rhythms are a factor for performance. With the knowledge that directions of travel may influence performance, we have yet another variable for the coaches and athletes to take into consideration in order to have the maximum performance. And it is yet another variable for the sports bookies and sabermetric scientists to play with.