Do you know the extraordinary things baseball reveals to us about sleep? (photo credit:

Do you know the extraordinary things baseball reveals to us about sleep? (photo credit:

One of the most important things a major-league baseball player needs to be able to do is determine which pitches thrown their way are strikes and which are balls.  The ability to differentiate between balls and strikes when the ball is going as much as 90 mph takes years of skill and practice and is one of the things that can make a good ball player great.  But new research shows that this fundamental part of being a great player can be compromised when players are fatigued.  In addition, another study shows that being overtired and sleepy on the field has a direct impact on the longevity of a player’s career.  Although these studies deal directly with baseball, the correlation to our own lives is clear.  When we aren’t getting the sleep we need, critical decision making skills we have honed all our lives can become compromised and not getting enough sleep means limits our potential.


The first study looked at how late-season fatigue impacts a player’s strike-zone judgment.  Baseball season begins in April and major league teams play 162 games in about 5 months.  This means they are travelling and playing almost every day with very few days off.  Over the course of the regular season, this can lead to fatigue.  The team conducting the study wanted to know if this accumulated fatigue had any impact on the player’s ability to gauge the strike zone.


The results of this study showed that strike-zone judgment across all major league teams had significantly degraded when the initial data from the beginning of the season in April was compared with the late season data gathered in September.  The study used something called plate discipline to gauge how accurately each player was as gauging their strike zone.  Plate discipline is determined by how often a player swings at pitches that are inside and outside the strike zone.  By using each player’s individual stats, the study was able to account for the inherent differences in plate discipline across players.  Additionally, when compared to information from the previous six seasons, the research team found that the same pattern of degradation was present regardless of the year.


These findings contradict conventional wisdom that says player’s plate discipline should improve over the course of the season as they get more time practicing and playing in games.  It opens the door for teams to actively implement fatigue management programs as a way to win more games.


A second study looked at the relationship between player sleepiness and longevity.  Using the Epworth Sleepiness Scale, the research team collected self-reported sleep data from players.  This data was then correlated with the number of years each player remained in the major league.  The results were striking.  The sleepier a player was, the less time he would remain in the league.  The relationship was so consistent and linear that it indicates that sleep may be predictive of performance.   This means that by managing their sleep better, players may be able to extend their careers.