This archive report was first published on 4 September 2019.
Scientists have discovered that using antibacterial mouthwash after exercise can significantly reduce the benefits of physical exertion, a new study has warned.
Researchers from the University of Plymouth conducted a study involving 23 healthy adults who were asked to run on a treadmill for 30 minutes on two separate occasions. The participants were then monitored for two hours after exercise, during which time they were given either antibacterial mouthwash or a placebo of mint-flavoured water to rinse their mouths.
The study found that when participants rinsed with the placebo, the average reduction in systolic blood pressure was minus 5.2 mmHg at one hour after exercise. However, when participants rinsed with the antibacterial mouthwash, the average systolic blood pressure was minus 2 mmHg at the same time point.
According to the study, published in the journal Free Radical Biology and Medicine, the results show that the blood pressure-lowering effect of exercise was diminished by more than 60% over the first hour of recovery, and totally eradicated two hours after exercise when participants were given the antibacterial mouthwash.
Lead author Dr Raul Bescos explained that the study challenges previous research which suggested that nitric oxide was not involved in the post-exercise response. Instead, the study found that nitric oxide degrades into a compound called nitrate, which is absorbed in the salivary glands and excreted with saliva in the mouth. Some species of bacteria in the mouth can use nitrate and convert it into nitrite, a molecule that can enhance the production of nitric oxide in the body.
Co-author Craig Cutler said: "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."
The study's findings have significant implications for health professionals, who are urged to pay attention to the oral environment when recommending interventions involving physical activity for high blood pressure.
