Article Summary:

• Using mouthwash after exercise lessens the positive effects of exercise on blood pressure
• Bacteria in the mouth can influence our cardiovascular health
• Better ways to get fresh breath include making a homemade mouthwash, staying well hydrated, and taking probiotic supplements

Antibacterial Mouthwash Increases Blood Pressure

Many of us squeeze in our workouts whenever we can find the time, say on weekend mornings before running some errands or during lunchtime on a workday. Others are single and ready to mingle at the gym’s juice bar after a good exercise session. But in all of those situations, a common thread is that we want to be as presentable as possible after our physical activity. Thus, we fix our hair, apply some deodorant, and use a little mouthwash before we come into contact with anyone else. However, you might want to skip the mouthwash portion of your post-workout grooming because new research suggests it may put a damper on one of exercise’s important benefits.

The study, which was conducted at the University of Plymouth in the United Kingdom, found that use of an antibacterial mouthwash after exercising markedly limits the reduction in blood pressure that a workout typically produces.¹Cutler, C.; et al. “Post-exercise hypotension and skeletal muscle oxygenation is regulated by nitrate-reducing activity of oral bacteria.” Free Radical Biology and Medicine. November 2019. Accessed 6 September 2019. http://www.sciencedirect.com/science/article/pii/S0891584919307610?via%3Dihub. These results are based on an investigation that included 23 men and women who fasted overnight and ran on a treadmill for 30 minutes the following morning.

After completing the run, the subjects rinsed their mouths with either antibacterial mouthwash or a minty flavored placebo at intervals of one, 30, 60, and 90 minutes post-workout. Both before the run and again at one hour and two hours afterward, blood and saliva samples were taken and blood pressure was measured; and the entire trial was conducted twice, on different days. Surprisingly, the examinations showed that the drop in blood pressure that normally occurs after a workout was reduced by more than 60 percent in the first hour after the run was finished.

How Could Mouthwash Influence Blood Pressure?

It is not entirely clear why mouthwash might affect our cardiovascular response to exercise, but one possibility is that certain oral bacteria produce nitric oxide, which helps increase the diameter of blood vessels, providing better blood flow to muscles. In fact, a 2013 study at the Karolinska Institutet in Stockholm, Sweden showed that using mouthwash independent of exercise may raise blood pressure levels.²Kapil, Vikas; et al. “Physiological role for nitrate-reducing oral bacteria in blood pressure control.” Free Radical Biology and Medicine. February 2013. Accessed 7 September 2019. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605573/. Of course, the current study is far too small to definitively answer any questions regarding blood pressure and mouthwash, but it certainly seems to contribute to our understanding of the effects of oral bacteria on blood pressure.

Our mouths are home to a wide array of bacteria. Some of them are harmful, like those that contribute to tooth decay and gum disease. But many others are beneficial and help in the digestive process. Therefore, the problem with antibacterial mouthwash likely lies in the fact that it not only destroys bacteria that cause bad breath, but also those that we need to manage our circulatory functions properly.

Natural Alternatives to Mouthwash

Beyond substantially reducing blood pressure after exercise, mouthwash has also been linked to oral irritations, wearing away of tooth enamel, and oral cancer. So, if you want to freshen your breath after an exercise session—or really any time throughout the day—there are safer options to choose than mouthwash.

Make your own mouthwash and keep it in a jar with a tight lid so you can bring it to the gym or anywhere else you might work out. A simple formula is one cup of filtered water, one teaspoon of baking soda, and three drops of peppermint essential oil. Just shake it up very well each time you are going to take a swig. It also might be helpful to hydrate better during your workout. Bad breath can arise when your mouth is dry, so drink plenty of water before and during your activity. And supplementing with probiotics every day can help strengthen the population of beneficial bacteria in your mouth and reduce the populations of the strains in your mouth that are associated with bad breath.