Health Farm

-- Time to pour your antibacterial mouthwash down the sink? Possibly, because it upsets bacteria in your mouth, interfering with a complex molecular mechanism that helps lower blood pressure after exercise.

During exercise blood vessels expand to increase blood flow to active muscles. The process, known as vasodilation, is the result of nitric oxide, which increases the diameter of the blood vessels. This is why beetroot, a food rich in nitrates, has caught the attention of endurance athletes.

However, the process relies on bacteria in the mouth to convert nitrates into a form that enhances the production of nitric oxide in the body. Nitrate is absorbed in the salivary glands and excreted with saliva in the mouth.

But that’s not going to happen when you’re swigging antibacterial mouthwash, according to conclusions drawn from a study involving 23 healthy adults.

Study participants ran on a treadmill for 30 minutes and had their blood pressure monitored for two hours following exercise. At one, 30, 60, and 90 minutes after the run, participants rinsed their mouths with either antibacterial mouthwash or the placebo substance (mint flavoured water) and gave blood and saliva samples for analysis.

After one hour of exercise, the placebo group’s systolic blood pressure dropped on average 5.2 milligrams of mercury (mm Hg), whereas the group rinsing with antibacterial mouthwash recorded a drop in blood pressure of only 2.0 mm Hg.

In other words, mouthwash reduced the blood pressure-lowering effects of exercise by more than 60% in the first hour of post exercise recovery.

Pro tip: Rinse with water.