Why Runners Should Brush Their Teeth After A Long Run

In 2026′s Tokyo marathon, runner and teacher Annie Tran said the secret to her speedy finish was a disposable toothbrush.

“Every runner knows that mile 20 is where we have to dig deep and find what little energy we have left. After brushing my teeth, I felt revived and refreshed,” she said on Instagram.

That’s one way of getting past “the wall”. But whether you’re running a marathon or not, runner Katy Laser pointed out an issue dentists say could be common among distance joggers – and might even be mitigated by a post-run brush.

Despite not eating much sugar or drinking many fizzy beverages, Katy said in a viral TikTok that her dentist called her out on some issues, which she later attributed to gel packs.

“In addition to [gels] being little packs of sugar… that are very sticky… your mouth gets drier when you run,” she explained. “It is just sticking to your teeth in a ‘desert mouth’… running gels are essentially the perfect storm of cavities”.

Ultra-runner and dentist Arden Young agreed.

“The amount and frequency of carbohydrate that an endurance athlete ingests during competition and training can wreak havoc in your mouth, increasing risk of enamel erosion, dental cavities, and inflammatory periodontal disease,” she shared on Instagram.

She added that most sports drinks are acidic. And while saliva helps to wash away both sugar and acids, as Katy explained, this is diminished during a run. This may be exacerbated by heavy breathing.

One paper found “high levels of poor oral health” among London 2012 Olympians; 76% had gingivitis, and 55% had caries (tooth decay).

Young advised drinking water after taking running gels. Pond Square Dental added that staying hydrated is the “first and most important step” when you’re on a long run.

If your dentist thinks you need higher-fluoride toothpaste, they can prescribe them. Good basic oral hygiene and fluoride rinses can go a long way, too.

Reducing the number of sugary snacks and gels you consume may also help.

And if those don’t work for very long runs, Dr Douglas Elliott at Elliott Orthodontics said “brushing your teeth before and after workouts” is worth a try too.