Mouthwashes reduce the blood-pressure-lowering effect of exercise
Exercise lowers blood pressure that's well known. Blood pressure is higher during the activity, which is a completely normal regulatory response, but after exercise it usually falls below the level it was at before the activity. Over the long term, exercise also has a positive effect on blood pressure.
However, researchers in England found that an antiseptic mouthwash can cancel out this effect.
Chlorhexidine inhibits bacteria in the mouth that convert nitrate into nitrite. Nitrite is a precursor of the vesseldilating nitric oxide (NO). The researchers attribute the rise in blood pressure in the mouthwash group to this. The mouthwash reduced nitrite production in the mouth by about 90 percent.
Another study supports this finding. In that study, 23 healthy adults ran on a treadmill for 30 minutes and were then asked to rinse their mouths immediately afterwards and again after 60 and 90 minutes. One of the solutions provided was only the control drink, while the other was the mouthwash being tested. That way the participants could not tell which sample they received. Blood pressure was measured in all participants before exercise and one and two hours after the workout.
The blood pressure of participants who rinsed with the control solution dropped as expected after exercise. On average, readings in this group were 5.2 mmHg lower than before. This level remained even two hours after the workout.
People who used the mouthwash after exercise only showed an average blood pressure drop of 2 mmHg, which had already disappeared by the final measurement after two hours.
This effect is due to the inhibited conversion of nitrate/nitrite into nitric oxide mentioned above. During exercise, more nitric oxide is produced so that the muscles get enough oxygen and nitric oxide is known to widen blood vessels. According to the researchers, bacteria in the mouth that help convert nitrate to nitrite and then to nitric oxide play a key role in this. If these bacteria are blocked by a chlorhexidine-containing mouthwash, the vessels cannot dilate sufficiently and the post-exercise blood pressure drop largely does not occur.
Because beetroot also works through this mechanism and can help lower blood pressure, it is possible that using a chlorhexidine-containing mouthwash after eating beetroot could cancel out that beneficial effect.
Sources
- https://www.sciencedirect.com/science/article/pii/S0891584912018229
- https://www.ncbi.nlm.nih.gov/pubmed/31369841
- https://www.medical-tribune.de/medizin-und-forschung/artikel/antiseptische-mundspuelung-kann-den-blutdruck-erhoehen/
- https://www.aerztezeitung.de/Medizin/Mundwasser-laesst-Blutdruck-steigen-251030.html
- https://www.iww.de/index.php/zr/allgemeine-zahnheilkunde/praevention-stickoxid-mehr-schaden-als-nutzen-durch-antibakterielle-mundspuelungen-f119629
- https://www.spektrum.de/news/mikrobiom-wie-sich-mundbakterien-auf-die-gesundheit-auswirken/1955962
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 01/2026).
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.
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.
