The weird reason you should never do this common thing before a workout

Vasodilation refers to the widening of blood vessels facilitated by the relaxation of smooth muscle cells within vessel walls in response to the production of a compound called nitric oxide. The process is enacted by moderate to intense physical activity and increases circulation and lowers blood pressure -unless, as a new study cautions, you happen to use anti-microbial mouth wash before your workout regimen.

New data published in the journal Free Radical Biology and Medicine posits that post-exercise hypotension and skeletal muscle oxygenation is hindered significantly by anti-bacterial agents found in mouth wash.


From the report:

“These findings show that nitrite synthesis by oral commensal bacteria is a key mechanism to induce the vascular response to exercise over the first period of recovery thereby promoting lower blood pressure and greater muscle oxygenation.”

The surprising impact of the “oral enivroment”  

Unbeknownst to many, oral bacteria play a monumental role in cardiovascular health. There are little communities of bacteria that live in your mouth that convert nitrate into the extremely helpful nitrite, which enhances the production of nitric oxide. If these communities are killed off blood vessels remain in their current state, irrespective of the degree of physical activity before imbibement.

The study was conducted by researchers from the University of Plymouth in partnership with the Centre of Genomic Regulation in Barcelona. The researchers monitored participants for two hours after having them run on a treadmill for about 30 minutes in two separate sessions. Following this, the study group rinsed out their mouth, 30, 60 and 90 minutes after exercise with either a minty placebo or a standard antibacterial mouthwash.

Blood pressure and salvia samples were taken at the two-hour mark revealed that those that used the antibacterial mouthwash reduced the blood-pressure-lowering effect of their workout by 60%  in their first hour of recovery in comparison with the placebo group. The species of bacteria that ensure the production of nitrite additionally help the compound become absorbed in the salivary glands. The molecule joins blood circulation just before being excreted as nitric oxide.

 “Scientists already know that blood vessels open up during exercise, as the production of nitric oxide increases the diameter of the blood vessels, increasing blood flow circulation to active muscles,” Lead author Dr Raul Bescos, from the University of Plymouth, explained to The Telegraph.  “What has remained a mystery is how blood circulation remains higher after exercise, in turn triggering a blood pressure-lowering response known as post-exercise hypotension. Previous research has suggested that nitric oxide was not involved in this post-exercise response – and only involved during exercise – but the new study challenges these views. 

The study titled, “Post-exercise hypotension and skeletal muscle oxygenation is regulated by nitrate-reducing activity of oral bacteria“, was published in the Journal Free Radical Biology and Medicine, and was authored by C.CutlerM.Kiernan, J.R.Willis. L.Gallardo-Alfaro, P.Casas-AgustenchD.White, M.Hickson, T.Gabaldon, and R.Bescos.