When you start to run, jump, or perform any workout a few things happen in your muscles, and nerves that tell your brain how much blood they’ll need to help you perform your chosen activity. Firstly, the actual movement and compression of muscle plays a role:
“Stretch and compression of the muscle is picked up by nerve endings, and they send messages back to the brain stem to help regulate pressure to drive blood flow during exercise,” Millar says.
But that’s just one way the brain and muscles communicate. The brain is also adept at receiving messages from a series of receptors all over the body that pick up on “metabolites” or by-products of energy burning and tell the brain to kick the heart into action that way. After receiving messages through these two pathways the brain can then respond: restricting blood vessels to increase blood flow, or increasing heart rate.
“Our study was focused mainly on the metabolic component,” he says. “We wanted to see the potential differences in the receptors that pick up on these metabolites and how might impact the blood pressure response.”
A Potential Warning Sign
It turned out that surprised that some of his participants had tiny differences in the genes that code for two particular receptors found in muscles, called TRPV1 and BDKRB2. These are two metabolite receptors that play a role in sending messages during the exercise pressor reflex that eventually end up in the brain stem — telling the body to increase or decrease heart rate or blood pressure.
In general, those with one particular variant had between a 22 and 23 percent greater differences in blood pressure than those without it. But the differences were more pronounced in men: when with one specific geneotype tended to have slightly higher blood pressure readings than their female counterparts with the same gene. For now, Millar isn’t sure why this is, and it will likely need further investigation.
Even more notably, when Millar had these participants perform another “mental stress task” he didn’t see these spikes in blood pressure — so it appears that exercise is a key ingredient for kicking these receptors into motion.
The changes were small, Millar notes, and not dire by any means, but they may serve as a way to identify people who may be particularly at risk for high blood pressure later on.
“This helps to provide a mechanism to show that there’s potentially a genetic component. But I think the goal would be that given the high blood pressure response to exercise and given the future risk of cardiovascular disease, this could be an identifier,” he adds.