Using Mouthwash May Not Be a Healthy Post-workout Practice After All: Here's Why

Mouthwash has become an essential part of people's daily regimen, makeup kit, or shaving kit. More than it making your breath smell good and cleaning 99.9% of oral germs as most advertisements claim. A study made a connection between exercise and the activity of bacteria in one's mouth.

How can working out and gargling mouthwash possibly be related? Regular exercise, such as 30 minutes on most days, lowers blood pressure because the activity makes one's heart stronger. Physical activity also helps maintain a healthy weight, which also controls blood pressure.

However, exercising doesn't automatically mean that blood pressure is reduced, it takes time and consistency. One to three months of regular exercise has to be maintained for it to have an impact on blood pressure.

How exactly the body does this is not fully understood yet by scientists. A study from Elsevier Journal experimented if oral bacteria triggers post-exercise hypotension (PEH), specifically the reduction of nitrate since it's common for people to shower and use mouthwash after working out.

In the experiment, eight women and fifteen men were being monitored as they did moderate treadmill cycles. They rinsed their mouths with either antibacterial mouthwash or a placebo mouthwash after exercising. Blood pressure was measured before, one hour and two hours after exercise.

Two hours after exercise, blood, and saliva samples were taken as well as the subjects' microvascular response to a reactive hyperemia test. Results showed that blood pressure was lowered after an hour, as expected, while there was an increase of circulatory nitrate after two hours.

Vasodilation occurs when blood vessels widen as a result of physical activity, increasing blood flow circulation as a response to the body producing nitric oxide, a compound that causes blood vessels to widen, releasing insulin and growth hormones.

Nitrate is Necessary

When nitric oxide degrades, nitrate forms then interacts with oral bacteria. Raul Bescos, a physiologist from Plymouth University, explains that 'research over the last decade has shown that nitrate can be absorbed in the salivary glands and excreted with saliva in the mouth.

When nitrate is produced and swallowed with saliva, blood circulation absorbs the compound and reduces it back to nitric oxide, keeping blood vessels wide and lowering blood pressure.

The experiment with 25 people shows that this nitrate and nitric oxide cycle was interrupted when they used mouthwash after exercising. They used mouthwash three more times after using the treadmill which resulted in more than a 60% reduction of systolic blood pressure.

Key to Good Health

'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.

Craig Cutler, another author on the team shared that, 'In effect, it's like oral bacteria are the 'key' to opening up the blood vessels. If they are removed, nitrite can't be produced and the vessels remain in their current state.'

Mouthwash may actually raise someone's blood pressure after exercise. 'The next step,' Cutler explains, 'is to investigate in more detail the effect of exercise on the activity of oral bacteria and the composition of oral bacteria in individuals under high cardiovascular risk. Long-term, research in this area may improve our knowledge for treating hypertension - or high blood pressure - more efficiently.'