Mouthwash can reduce the blood-pressure-lowering effect of exercise

Exercise lowers the blood pressure - that's well known. The readings are higher during a workout, which is a completely normal regulatory response, but blood pressure usually falls after exercise below the level it was at before the physical activity.

British researchers, however, found that an antiseptic mouthwash cancels out this effect.

They observed 19 young, healthy volunteers who did not use mouthwash during the first observation week. In the second week the participants used chlorhexidine-containing mouthwash. The first week served as a baseline for comparison.

Chlorhexidine inhibits bacteria in the mouth that convert nitrate into nitrite. Nitrite, in turn, is a precursor of the vesseldilating nitric oxide (NO). The researchers say this explains why the mouthwash groups blood pressure rose. The mouthwash reduced nitrite production in the mouth by 90 percent.

Another study supports this finding. In that study, 23 healthy adults were sent to the treadmill for 30 minutes and were then asked to rinse their mouths with mouthwash immediately afterward and again after 60 and 90 minutes. Some of the solutions offered were only the control rinse, while others were the mouthwash being tested. In this way the participants could not tell which sample they received. Blood pressure was measured in all participants before and one and two hours after the exercise.

The blood pressure readings of the participants who rinsed with the control solution fell as expected after the exercise. On average, readings in this group were 5.2 mmHg lower than before. This lower level was still present two hours after the workout.

Those who used the mouthwash after exercise showed only an average blood pressure reduction of 2 mmHg, which had already disappeared by the final measurement two hours later.

This effect is due to the inhibited conversion of nitrate/nitrite into nitric oxide mentioned above. During exercise, more nitric oxide is produced to provide muscles with enough oxygen; nitric oxide is known to dilate blood vessels. According to the researchers, oral bacteria that convert nitrate into nitrite and then into nitric oxide play a key role in this process. If these bacteria are blocked by a chlorhexidine-containing mouthwash, the vessels cannot dilate sufficiently and the post-exercise drop in blood pressure largely does not occur.

Because beetroot also works through this mechanism and can help lower blood pressure, it's possible that using a chlorhexidine-containing mouthwash after eating beetroot could cancel out this positive effect.

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This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands monitor their blood pressure every day. Our content is based on carefully researched, evidence-based data and is continuously updated (as of 04/2024).

Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.

Mouthwash can reduce the blood-pressure-lowering effect of exercise

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