Mouthwash Should Not Be Used After Exercising, Warns Study

Mouthwashes, as shown in TV ads, neutralizes all the bacteria hidden in people’s mouths and instantly assure dental hygiene. But have you ever wondered what it means to those beneficial microorganisms in and around your mouth?

As surprising as it can be, using a mouthwash can affect much more than just your dental health, demonstrated a 2019 study.

The researchers found that the simple act of using mouthwash post-exercise can reduce one of the benefits of working out: reducing blood pressure levels.

The Study:

The researchers investigated whether the nitrate-reducing activity of oral bacteria is important to trigger post-exercise hypotension. The study included 23 healthy individuals who completed two treadmill trials at moderate intensity. While some of them were asked to rinse their mouth with an antibacterial mouthwash solution after exercise, in order to inhibit the activity of oral bacteria, others were given a placebo mouthwash. They then measured the participants’ blood pressure immediately after the exercise as well as later during their rest period.

The findings:

• One hour after the exercise, the average reduction in systolic blood pressure (-5.2 mmHg) was observed in the placebo group
• Reduction of blood pressure in the group that rinsed their mouths using the mouthwash was much lower
• The use of antibacterial mouthwash had lowered the systolic blood pressure reduction by over 60%
• Two hours after the exercise, the mouthwash group exhibited no sign of blood pressure reduction stemming from the exercise, whereas, those in the placebo group continued to show a significant reduction compared to their pre-exercise blood pressure levels

“This is the first evidence showing that the nitrate-reducing activity of oral bacteria is a key mechanism to induce the acute cardiovascular response to exercise during the recovery period in healthy individuals," said the authors in their paper published in Free Radical Biology and Medicine.

Even though it is just a small study, the findings highlighted the fact that not all bacteria are necessarily bad for human beings. The study also emphasized that ingesting antibacterial chemicals that indiscriminately terminate mouth-dwelling microorganisms could hamper important biological processes that are crucial for our well being.