Vigorous exercise is good for your mind and body. But a surprising new study of athletes finds it may actually be bad for your teeth.
 

The New York Times reports the new research, published The Scandanavian Journal of Medicine & Science in Sports, showed heavy training may contribute to dental problems in unexpected ways.
 

Researchers with the dental school at University Hospital Heidelberg in Germany and other institutions recruited 35 competitive triathletes and 35 age- and gender-matched healthy adults who were not athletes.
 

All visited the hospital’s dental lab for a full oral  exam and completed questionnaires about their diets, including consumption of sports drinks and other beverages, their normal oral hygiene routines, and their exercise habits, if any.
 

Fifteen of the athletes also completed a strenuous run, during which their saliva was collected. Then the researchers compared the groups’ teeth and saliva, which turned out to be different in telling ways.
 

What they found was that the athletes showed significantly greater erosion of their tooth enamel and tended to have more cavities, with the risk increasing as an athlete’s training time grew. Over all, the more hours that an athlete spent working out, the more likely he or she was to have cavities.
 

One possible explanation: During strenuous workouts the amount of saliva athletes produce progressively lessens, meaning that their mouths became drier, regardless of whether they consumed water or other beverages during the workout. The saliva’s chemical composition also shifted, growing more alkaline as the workout continued. Excess alkalinity in saliva is thought to contribute to the development of tartar plaques on teeth and other problems.
 

 “We had thought sports drinks and nutrition might have the most detrimental influence on dental decay,” said lead researcher Cornelia Frese, M.D., a senior dentist at University Hospital Heidelberg, “but we saw no direct link” between them.