Exercise Like a Drug in Heart Disease, Study Finds

January 23, 2003

WASHINGTON (Reuters) - Exercise can act like a drug on the blood vessels, reducing the risk of heart disease by literally getting the blood flowing, U.S. researchers said on Thursday.

It works in a surprising way, reducing inflammation, which has recently joined high blood pressure and high cholesterol as a leading known cause of heart disease, the researchers said.

The blood stresses the walls of blood vessels as it passes over them, reducing inflammation in a way similar to high doses of steroids, the researchers report in Friday's issue of Circulation Research.

"Inflammation in blood vessels has been linked to atherosclerosis, a hardening of the arteries, and here we see how the physical force of blood flow can cause cells to produce their own anti-inflammatory response," Scott Diamond of the University of Pennsylvania's Institute for Medicine and Engineering, said in a statement.

"Conceivably, exercise provides the localized benefits of glucocorticoids -- just as potent as high doses of steroids, yet without all the systemic side effects of taking the drugs themselves," added Diamond, who led the study.

"Perhaps this is a natural way in which exercise helps protect the vessels, by stimulating an anti-inflammatory program when the vessels are exposed to elevated blood flow."

The findings could help explain why exercise works so well to reduce the risk of heart disease, Diamond said.

"We're not talking about running a marathon here. We're just talking about getting the blood moving at high arterial levels," he said.

Studies in recent years have found that cells and chemicals linked with inflammation can be found in arterial clogs, and much research is now focusing on ways to reduce this inflammation. For instance, teams are investigating whether giving patients antibiotics or anti-inflammatory drugs lowers their risk of heart disease.

Diamond has worked using human arteries in the lab but wants to move into animals to confirm his hypothesis.

"Think of blood flow as a stream -- whenever a stream branches off you get small areas of recirculation eddies or pools of stagnant water," he said.

"These same situations of disturbed flow irritate the endothelium (the lining of the blood vessels). When blood vessels branch off, all the arterial flotsam -- fats and activated blood cells -- can clump and stick at these hot spots for atherosclerotic plaque formation," he added.

"Perhaps, elevated blood flow may alter these disease-prone regions to relieve some of the localized inflammation."