Exercise has a beneficial effect on the lining of arteries in postmenopausal women, according to a recent University of Alberta review. When the cells lining the arteries are healthy, this could help prevent heart diseases such as coronary artery disease.
Researchers analyzed data from 35 studies and found in two-thirds of those studies, participants showed improvement in at least one marker of endothelial function, with positive changes in both large and small blood vessels, explains Kyra Pyke, co-author on the study.
"Endothelial cells line the inside of our blood vessels and regulate vascular function. How well these cells are functioning is a valuable indicator of heart health because they serve as a predictor to the development of atherosclerosis, the buildup of plaque on the artery walls.
Exercise is already known to help with endothelial function in general, Pyke says. It increases blood flow to working muscles, including the heart, and the friction of blood moving through the blood vessels stimulates the endothelial cells and increases the activity of a particular enzyme that makes a molecule called nitric oxide.
“Nitric oxide helps support the dilation of blood vessels, which is important for the delivery of oxygen to tissue,” said Pyke, adding nitric oxide also helps prevent plaque from forming in the arteries.
Focus on research about women, for women
Pyke and co-authors wanted to summarize knowledge and identify gaps in understanding how exercise affects postmenopausal women specifically. Many other studies are done with only male participants or don’t distinguish between male and female participants. Since sex hormones can affect endothelial function, it’s important to consider the effects on men and women separately, said Pyke.
Estrogen, for example, is known to increase the formation of nitric oxide. Pyke’s lab previously studied the effect that changes in estrogen over the course of a menstrual cycle had on premenopausal women, and wanted to delve further into what happens with the more chronic decline in estrogen that comes with menopause.
A good way to assess endothelial function is what’s called a flow mediated dilation test, where a blood pressure cuff is placed on the forearm and inflated for about five minutes, until the blood vessels downstream of the cuff dilate. When the cuff is released, the blood rushes back into the forearm through the brachial artery in the upper arm.
In many of the studies the researchers reviewed, a flow mediated dilation test was done before and after an exercise intervention. The bigger the artery diameter gets during the test, the better the endothelial function.
Positive side-effects of exercise
Pyke stresses more research is still needed in this area, because the studies her team looked at vary widely in the type, intensity and frequency of the exercise being done. And though the majority of studies saw a beneficial effect of exercise on endothelial function in postmenopausal participants, a third of studies did not. This suggests personal characteristics that may influence the endothelial response to exercise also need to be considered, such as whether women are receiving hormone therapy or how long they have been in menopause.
But even though exercise wasn’t 100 per cent effective in boosting endothelial function among postmenopausal women, Pyke points out it has a host of other potential benefits that make it worth pursuing.
Additionally, while most other heart health interventions would never be implemented before an actual diagnosis, lifestyle interventions like exercise are preventative and can be incorporated at any point.
“Compared to drugs, which may have negative side-effects, many of the side-effects of exercise are positive,” said Pyke.
“When you’re exercising to improve your heart health, you’re also going to improve your bone health, it has antidepressant effects — a whole myriad of positive impacts.”
Article courtesy of University of Alberta folio
