The next two months will be the usual sweat fest for those of us who like to spend large amounts of time outdoors, especially doing physical activities.

And it's perhaps the most appropriate time to consume "sports drinks" to replace electrolytes, particularly sodium and potassium, lost in sweat.

Just be mindful what the sugar and acid in these drinks might do to your teeth, particularly if you sip them over long periods of time. And you may want to brush ASAP.

Latest study

I was reminded of the detriments of sports and energy drinks and foods after reading about a somewhat surprising study published last month in the "Scandinavian Journal of Medicine & Science in Sports" and highlighted by the National Institutes of Health.

The study of 35 triathletes, who spent about 10 hours a week swimming, biking or running, and 35 "non-exercising" individuals found that the triathletes had significantly higher tooth erosion. The German dental researchers also found that the athletes who engaged in more weekly training had more erosion than those who trained less.

Both the athletes and nonathletes had an average age of 36, but the athletes were significantly lighter, with lower BMIs, which is typically associated with better health.

The athletes, 46 percent of whom consumed sports drinks while training and 72 percent ate energy bars or gels while training, were examined for cavities and tooth erosion. They also took saliva tests both at rest and while exercising. All results were compared to the control group.

Researcher Cornelia Frese told "Runner's World" that consumption of high carbohydrate foods, including sports drinks, gels and bars during training, can lower the mouth's pH below the critical mark of 5.5.

"That can lead to dental erosion and caries (cavities)," says Frese, adding that breathing through the mouth during hard exercise also contributes to the problem. "The mouth gets dry and produces less saliva, which normally protects the teeth."

While various dental tests revealed no statistically significant difference in cavities between the two groups (although the athletes who trained the most had the most cavities), the triathletes suffered significantly higher tooth erosion.

With a grain of sugar

Two local dentists who are avid endurance athletes, Dr. Michael Bannister and Dr. Jason Annan, have mixed feelings about the study. Annan, in particular, thought the number of people studied was too low and that the "cause and effect are very hard to establish."

Both Bannister and Annan say that the health benefits of leading an active life far outweighs any higher risks to tooth health, but that concerns about tooth decay from sugary, relatively acidic sports drinks are well-founded and applies to everyone.

Bannister, an avid, long-time local cyclist, says that any drink that contains sugar or other carbohydrates, particular more acidic sports drinks, can be a problem if exposed to teeth for a long time.

"The same amount of a sugary drink over a short time is less problematic than that same amount sipped steadily over a much longer time, which allows the bacteria in the mouth to consume the sugar with acid as a by-product over a longer period of time," says Bannister.

The acid, he stresses, will lead to demineralization of the tooth, weakening it and leading to dental cavities or tooth decay.

"Sports drinks can be more problematic because they have a lower pH, or are more acidic, and contain carbohydrates," says Bannister. "Parents and children might feel like the sports drinks are less damaging to teeth because they don't taste as sweet as a soda, but the harmful effects can be worse because of the lower pH already coupled with the sugar exposure."

He urges moderation with sports drinks, using them to replenish electrolytes and calories lost during exercise, and not to use them as a casual drink.

Saliva saves teeth

Both Bannister and Annan, an avid runner who competed at both Wando High School and Duke University, thought the issue of lower saliva was an interesting observation in the study.

"To me, the stand out point in the (study's) abstract was that a lower saliva flow was noted in the triathlete group," says Annan, who is 40 and finished in the top 100 of this year's Cooper River Bridge Run.

"We know that low saliva flow goes to dry mouth, which is a huge risk factor for dental decay," says Annan, noting that athletes aren't alone in having reduced saliva flow.

"Much of the population takes medicines that will reduce saliva flow - the statins for cholesterol, for example - and this is an infinitely bigger problem than the small subset of people that exercises a lot."

Bannister describes saliva as having a "cleansing and acid-buffering effect" and the time period in which a sports drink or energy food, such as a bar or gel, is consumed matters.

"If it is consumed at one time, then the acid effect is minimal. If it is consumed in small amount over a long period of time, then the acid effect is greater," says Bannister. "With exercise or without exercise, the oral hygiene habits of minimizing time exposed to carbohydrates, thorough brushing of the teeth twice daily and daily flossing are the same."

Reach David Quick at 937-5516.