May 01, 2005
Sunday

Washington - Blood vessels may respond positively to changes in diet and exercise in those at risk for heart disease as soon as eight weeks after starting the regimen, according to a study presented Friday at an American Heart Association scientific conference here.

Canadian researchers found improved exercise capacity, increased flexibility in the main artery of the neck and an average weight loss of about 3-1/2 pounds among the 38 patients taking part in the trial.

"Our lifestyle-management program appears to improve the health of the vasculature, so it might lower the risk of high blood pressure, diabetes, heart attacks and stroke," said Kunihiko Aizawa, a researcher at the University of Western Ontario in London, Ontario, who presented the findings. "We found that there probably are some things that happen in even eight weeks."

The study presented preliminary data from a larger, longer-term randomized trial involving nutrition changes and activity counseling in patients at risk for heart disease.

"There have been studies looking at diet and exercise to prevent or treat cardiovascular disease before," said Dr. Robert Petrella, primary investigator for the study and an associate professor of medicine at the university. "The difference here is that the calories and composition of the diet and physical activity prescribed were matched to fitness level in an individually tailored fashion, and delivered through a family-practice setting as opposed to a hospital or laboratory."

The intervention randomly assigned the patients, all with borderline high blood pressure or near-diabetic and an average age of 53.3 years, either to receive the diet and exercise program or typical lifestyle counseling. Most participants were women.

One in three American adults has high blood pressure and two-thirds to three-fourths of people with diabetes die of some form of heart or blood-vessel disease, according to the Heart Association, "so anything we can do to reduce their lifetime risk is important," Petrella said.

The diet change relied on a Mediterranean-style diet, high in fruits, vegetables, bread, other cereals, potatoes, beans, nuts and seeds, but low-to-moderate amounts of dairy, fish and poultry. The Heart Association has recognized such a diet as offering protection to the heart and circulatory system for four years.

Treadmill tests were done to measure exercise capacity based on the maximum volume of oxygen exchanged during exercise. Researchers found that the average volume increased from 32.1 milliliters per minute to 35.3 milliliters during the first eight weeks for those on the program. The average body weight fell from 203.5 pounds to 200 pounds.

"We were surprised that we saw such a weight reduction with the Mediterranean diet," Petrella said. "It was not a weight-reduction program."

The researchers also did ultrasound tests to measure patients' hearts and blood vessels at rest, looking for changes in the thickness or elasticity of the heart and also major arteries in the arm and neck. The thicker and less elastic the arteries are, the greater the load on the heart.

The tests showed that the only significant improvement was in the carotid (neck) artery, which increased elasticity by an average of 16 percent. There was no significant change in blood pressure between the two groups.

But Petrella said other physical factors might improve for patients getting the intervention as they're followed for a full year.

On the Net:

www.americanheart.org

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