At mile 18 of a marathon, some of the fittest people on earth reach into their running vests for a fistful of candy. Many elite athletes swear by this approach: after roughly ninety minutes of exertion the body is burning carbohydrates faster than a single pasta dinner can replenish, and candy can provide a fast dose of simple carbs that is lighter, cheaper, and often more palatable than a commercial gel.
I’m not here to settle the gel-versus-candy debate. What I do want to focus on is a different consequence of that mid-race sugar hit: the impact on your teeth and the oral microbiome.
The moment you begin breathing through your mouth — on a hard run, a long ride, or an intense gym session — your mouth dries out and the pH can fall. Saliva is your mouth’s natural defense: it bathes enamel in minerals and buffers that repair and neutralize acid. When saliva flow drops because of mouth breathing, your enamel loses protection and becomes more vulnerable to acid attacks.
Put plainly, athletes who regularly breathe through their mouths are at higher risk for cavities than habitual nose breathers. That can feel unfair: a commitment to training shouldn’t have to mean extra dental work. Fortunately, there are practical steps athletes can take to protect their oral health without sacrificing performance.
My must-haves for athletes (whether you’re training for Ironman or casually hitting the treadmill in your garage)
✔️ Electrolytes. Beyond hydration and performance, electrolytes help maintain the minerals in your saliva that aid enamel repair. Saliva carries calcium and phosphate to the tooth surface and contains buffers that neutralize acid — these processes depend on an adequate mineral balance. During long training sessions, use an electrolyte product you trust to support both performance and oral health.
✔️ Nitrate-supporting mints. The bacteria at the back of the tongue convert dietary nitrate into nitric oxide, a molecule that dilates blood vessels and improves blood flow to working muscles. This nitrate-to-nitric-oxide pathway becomes more important as we age because natural nitric oxide production declines. Targeted mints or foods that support that pathway can be a convenient on-demand boost to circulatory support during long or intense efforts.
✔️ Nano-hydroxyapatite toothpaste that’s microbiome-friendly. Training exposes enamel to repeated acid challenges from mouth breathing and acidic fuels. Brushing daily with a toothpaste containing nano-hydroxyapatite helps replenish the same mineral your teeth are made of and can support enamel repair while being gentle on the oral microbiome. Recent clinical work has shown promising results for hydroxyapatite formulas in protecting enamel, making them a solid option for athletes seeking an alternative or complement to fluoride-based products.
✔️ Xylitol gum or mints. Chewing a piece immediately after a workout stimulates saliva flow and speeds recovery of the mouth’s protective environment. Xylitol is not fermentable by Streptococcus mutans, the primary cavity-causing bacteria, so chewing xylitol gum both restores saliva and deprives harmful bacteria of an easily usable food source. Keep xylitol gum or mints in your bag for post-exertion use.
✔️ Mouth tape. Some high-performance athletes use mouth tape to encourage nasal breathing during sleep and some training sessions. Consistent nasal breathing supports better sleep quality, maintains saliva flow, and preserves the beneficial bacteria on the tongue that participate in the nitrate-to-nitric-oxide conversion. If you’re curious about mouth tape, introduce it gradually and consider consulting a clinician experienced in airway health to ensure it’s appropriate for you.
If you insist on eating candy during long workouts, remember this: it’s not just the total grams of sugar that matter, it’s how long that sugar sits on your teeth. Nursing a pack of sticky candies over an hour does more harm than consuming the same amount quickly. After consuming candy, rinse or swish with water to remove sticky residues and encourage saliva to wash away fermentable sugars.
Small habits add up. Your mouth is not separate from your training or recovery; it is part of the system that builds fitness. Tuning oral care to match your athletic routine can protect your enamel, preserve a healthy oral microbiome, and help you stay on track without unnecessary dental setbacks.
– Dr. B
P.S. For more on common causes of sudden adult cavities, consult reputable dental resources or speak with your dentist. P.P.S. If you cannot take a full, comfortable breath through your nose at rest, consider an airway-focused dental evaluation; a clinician trained in airway health can assess whether structural or functional issues are affecting your breathing and oral health.