Why Your Mouthwash Matters

Don't rinse away your gains! Anti-bacterial mouthwash can interfere with the benefits of exercise.

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Having trouble hitting your workout goals? A new study revealed that using anti-bacterial mouthwash could be rinsing away your results and that your oral microbiome could be a necessary component of blood pressure regulation.

Here’s the deal: When you exercise, your blood vessels open up, boosting blood flow to engaged muscles and subsequently lowering blood pressure. But researchers were curious why an individual’s blood pressure would stay elevated after exercise — a process called post-exercise hypotension — and suspected that it had to do with the conversion of nitrates into nitric oxide, which causes your vessels to dilate. Because certain bacteria are known to facilitate this alteration, scientists blocked nitrate conversion in study volunteers, then had them run on a treadmill for 30 minutes. Afterward, participants either rinsed with an anti-bacterial mouthwash or with a placebo.

An hour postworkout, the blood pressure of the placebo group was about -5.2 mmHg lower, but in the anti-bacterial group, it was only -2.0 mmHg lower. The conclusion: The mouthwash killed o the bacteria responsible for converting the nitrates into nitric oxide, preventing the body from lowering blood pressure and promoting blood flow.

“Pay attention to your oral health to get the maximum cardiovascular outcome of exercise,” says Raul Bescos, Ph.D., professor of dietetics and physiology at the University of Plymouth in the U.K., adding that you should only use anti-bacterial mouthwash if prescribed for gum disease.