CHICAGO, April 8 (Xinhua) -- No pain means no gain when it comes to reaping exercise benefits for people with peripheral artery disease (PAD), according to a study at the Northwestern Medicine in the U.S. state of Illinois.
For the study, 305 people with peripheral artery disease at four medical centers were randomized to high-intensity exercise, low-intensity exercise or a control group that got telephone calls that were not about exercise. Those randomized to an exercise intervention were asked to walk up to 50 minutes per session, five days a week. Those in high intensity were asked to walk at a pace that was fast enough to elicit ischemic leg symptoms during exercise. Those randomized to low intensity were asked to walk at a comfortable pace that did not induce ischemic leg symptoms.
Intensity was monitored remotely using an ActiGraph activity monitor that participants wore during exercise. These data were uploaded to the study website and viewed by study coaches. The six-minute walk, treadmill testing and patient-reported outcomes were measured at baseline and at 12-month follow-up.
Patients who participated in high-intensity walking exercise significantly improved the distance they could walk in six minutes compared to either the low-intensity group or the control group. The high-intensity exercise group also significantly improved the length of time they could walk on the treadmill at the end of the study, compared to each of the other two groups.
"Patients with PAD should be advised to walk for exercise at a pace that induces ischemic leg symptoms in order to get a benefit," said lead investigator Mary McDermott, professor of medicine at Northwestern University Feinberg School of Medicine. "Exercise is the most effective non-invasive therapy to improve walking in people with PAD."
In the next step, the research is to determine the biologic explanation for the finding that ischemia of the lower extremities appears necessary to gain benefit from walking exercise in people with PAD.
About 8.5 million in the United States and about 250 million people worldwide have lower extremity peripheral artery disease. People with PAD have blockages in their arteries that slow or stop the blood flood flow to their legs. As a result, they have pain and difficulty walking even short distances.
The study was published Tuesday in JAMA.
Northwestern Medicine is the collaboration between Northwestern Memorial HealthCare and Northwestern University Feinberg School of Medicine, which includes research, teaching and patient care. Enditem