Exercise is known to reduce blood pressure but the activity of bacteria in our mouths may determine whether we experience this benefit, according to new research. An international team of scientists has shown that the blood pressure lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash, rather than water showing the importance of oral bacteria in cardiovascular health.
The researchers now suggest that health professionals should pay attention to the oral environment when recommending interventions involving physical activity for high blood pressure. The study was led by the University of Plymouth in collaboration with the Centre of Genomic Regulation in Barcelona (Gabaldon’s lab), Spain, and was published in the journal Free Radical Biology and Medicine.
Lowering of blood pressure
“Previous research has suggested that nitric oxide was not involve in this post exercise response and only involved during exercise but the new study challenges these views.”It’s all to do with nitric oxide degrading into a compound called nitrate; which for years was though to have no function in the body. But research over the last decade has show that nitrate can be absorb in the salivary glands and excreted with saliva in the mouth.
“Some species of bacteria in the mouth can use nitrate and convert into nitrite a very important; so molecule that can enhance the production of nitric oxide in the body. And when nitrite in saliva is swallow; part of this molecule is rapidly absorb into the circulation and reduce back to nitric oxide. This helps to maintain a widening of blood vessels; which leads to a sustain lowering of blood pressure after exercise. “They want to see whether blocking nitrate’s ability to convert into nitrite by inhibiting oral bacteria; would have any effect on post exercise hypotension.”
Twenty three healthy adults were ask to run on a treadmill for a total of 30 minutes on two separate occasions; after which they were monitor for two hours. On each occasion at one, 30, 60 and 90 minutes after exercise they were ask to rinse their mouths with a liquid either antibacterial mouthwash (0.2% chlorhexidine) or a placebo of mint-flavour water. Neither the researchers nor the participants knew which liquid they were rinsing with.
Lowering effect of exercise
These results show that the blood pressure lowering effect of exercise; was diminish by more than 60% over the first hour of recovery; also totally abolish two hours after exercise; so which participants were give the antibacterial mouthwash. Previous views also suggest that the main source of nitrite in the circulation after exercise was nitric oxide form during exercise in the endothelial cells (cells that line the blood vessels). However, the new study challenges this.
Craig Cutler, study co-author who conduct the research as part of his Ph.D. at the University of Plymouth, said: “These findings show that nitrite synthesis by oral bacteria is hugely important; so in kick starting how our bodies react to exercise over the first period of recovery; promoting lower blood pressure and greater muscle oxygenation. “In effect, it’s like oral bacteria are the ‘key’ to opening up the blood vessels. If they are remove, nitrite can not be produce; also the vessels remain in their current state.
“Existing studies show that, exercise aside; antibacterial mouthwash can actually raise blood pressure under resting conditions; so this study follow up and show the mouthwash impact on the effects of exercise. “The next step is to investigate in more detail the effect of exercise on the activity of oral bacteria; also 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.”