Your Mouthwash Could Cancel Out Your Workout

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Even if you don't floss every day, you're most likely taking care of your teeth the best you can. Your dental routine might even involve a swish of Listerine, or whatever you buy to buff up your pearly whites and gums after brushing. Take care when you use it, though, because it could be zeroing out your gym time.

Health researchers in Spain and the U.K. have just released a study examining the connection between working out, heart health, and oral care. One reason physicians urge exercise is to help keep your blood pressure in check. When study participants used mouthwash up to 90 minutes after a workout, their blood pressure was just 40 percent as low as it should be. In other words, when mouthwash destroys the beneficial bacteria in your mouth after exercise, it interrupts what makes exercise healthy in the first place.

This effect is weird, but not unknown. Previous studies have shown that even without the trip to the gym, "antibacterial mouthwash can actually raise blood pressure under resting conditions," says coauthor Craig Cutler.

Mouthwash isn't the only purchase we make with dubious effects for our post-workout health. Last month, researchers found that elite athletes are more likely to show signs of oral diseases, thanks to the composition of energy drinks like Gatorade. Another recent study found that protein shakes don't actually do much for after-workout muscle pain. There is some good news, though: Water is still your best bet for top-quality hydration — and it comes at a much lower cost than any of the liquids above.