Asthma may be to blame for poor performance

Having a bad day on the soccer field or treadmill? Maybe you can blame asthma.

According to a new study of 107 varsity athletes representing 22 sports, 39 percent experienced a constricting of their airways while working out. The constriction, caused by large amounts of cool, drier air entering the lungs during exercise, often is not severe enough to cause wheezing and chest tightness, so many athletes just chalk up lackluster performances to being tired or out of shape.

Exercise-induced asthma has been studied mostly in top athletes, but people working out recreationally should be cognizant of the risk as well.

Jonathan Parsons, associate director of Ohio State Medical Center's Asthma Center and lead author of the study, says that if you are working out regularly but are inexplicably tired or don't see fitness or performance gains in proportion to the time you spend training -- you're running more than ever, but your 5K time hasn't budged -- you should see an allergist or pulmonologist.