Coaches, owners and fantasy-league traders beware. Scientists have discovered a negative association between a professional athletes' longevity and their level of daytime sleepiness. 

Researchers presenting their studies Tuesday at SLEEP 2012, the 26th annual meeting of the Associated Professional Sleep Societies in Boston found that sleepier athletes had significantly shorter career spans compared to the average professional athlete.

Researchers looked at two sports: football and baseball. They found that less sleepy football players tended to remain with their drafting NFL teams after college and sleepier baseball players had higher attrition rates compared to MLB averages.

"A team's ability to accurately judge a prospect or a potential trade in terms of the value they will get for that player is what makes or breaks many professional sport teams," said sleep advisor and principal investigator Dr. Christopher Winter.

"These studies demonstrate that a simple evaluation of sleepiness may be a powerful tool to add to the list of tests athletes already undergo, such as the Wonderlic Cognitive Abilities Test and the 40-yard dash," he said.

The football study consisted of 55 randomly selected college players who were selected to play for the NFL. Researchers found that sleepier football players only had a 38 percent chance of staying with the team that originally drafted them, compared to 56 percent of the less sleepy players, who researchers considered to be a "value pick" because they were more likely to stay with their original team.

In the baseball study that consisted of 40 randomly selected baseball players, researchers found players who reported higher levels of daytime sleepiness had attrition rates of 57 percent to 86 percent, which was significantly above the 30 to 35 percent MLB average.

In both the studies, sleepiness was measured by using the Epworth Sleepiness Scale (ESS), a short questionnaire that can be used for detecting excessive daytime sleepiness (EDS).

Researchers said not only can measuring sleepiness help a team decide who to draft, it can also help players themselves correct the underlying issues causing their sleepiness, potentially prolonging their career.