The researchers looked at 35 triathletes, and 35 “non-exercising controls.” After gathering some rudimentary information about their demographics, how much they trained, and their predilection for sports drinks, protein bars, and energy gels, they had some dentists check out the participants’ teeth. Unfortunately, the dental examiners knew who was an athlete and who wasn’t: “It was not feasible to blind examiners with regard to test and controls, since the appearance of athletes (figure, muscular mass, and clothes) was obvious to the investigators,” the study reads. Participants’ teeth were rated using the Basic Erosive Wear Examination (BEWE), and received a score based on how closely their teeth resembled wind-worn canyons, I guess.

Teeth cataloged, it was then time for saliva. The participants chewed a piece of wax for five minutes, and then the researchers dunked a pH strip in the resulting spit pool. Fifteen of the athletes then volunteered to repeat this distinguished task whilst running.

Athletes’ BEWE scores showed that they were at a medium risk for tooth erosion, whereas the regular schmo controls were at a low risk. While athletes did have more cavities, that was associated with how much they trained. More workout hours logged per week meant a higher risk of cavities.

Everybody’s spit had pretty neutral pHs when they were just sitting around the lab, jawing on some wax. But, and this is where it gets interesting, athletes saliva had a significantly higher pH (meaning it was more basic, or alkaline) during the workout. They also produced less saliva overall.

There’s a type of protein in saliva, the researchers explain, that is thought to help prevent tooth erosion. The link between working out, saliva pH, and tooth decay, could be because the more alkaline saliva messes with that protein’s protective instincts. The researchers didn’t find any associations with sports drinks.

Triathletes (and Olympians) are a little more extreme when it comes to athleticism, of course, than your average hop-on-the-treadmill-a-couple-times-a-week Joe. It is interesting to think, though, that even if you avoid sugary drinks and brush twice a day, you could be putting your teeth at a different kind of risk when you go to the gym. But, you know, you should still go.