No pain, no gain in exercise for peripheral artery disease


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No pain, no gain when it comes to reaping the benefits of exercise for people with peripheral artery disease (PAD), reports a new Northwestern Medicine study.

In people with peripheral artery disease, walking for exercise at an intensity that induces ischemic leg pain (caused by restricted blood flow) improves walking performance (distance and walking time), the study found. Walking at a slow pace that does not induce ischemic leg symptoms is no more effective than no exercise, the study showed.

This randomized trial is the first to show that a home walking exercise program improved the ability to walk in people with peripheral arterial disease when exercise was performed at a high intensity that induced ischemic symptoms in the legs, but not when the Exercise was performed at low intensity with no ischemic leg symptoms.

“We have shown that you have to walk to cause ischemic leg pain and reap the benefits,” said lead researcher Dr. Mary McDermott, professor of medicine at Northwestern University Feinberg School of Medicine. “It will decrease over time, and most people will eventually be able to walk more without discomfort.”

The study was published in JAMA April 6, 2021.

McDermott’s earlier research suggested that pain during exercise prevented many people with PAD from walking.

While the trial did not identify the biological changes that lead to improved gait, McDermott said previous research shows that intensive exercise stimulates certain biological pathways that promote better mitochondrial activity, the cell’s chemical energy source.

“Perhaps for people with PAD, exercise promotes the growth of new small blood vessels in their muscles,” McDermott said.

Approximately 8.5 million in the United States and about 250 million people worldwide have lower extremity peripheral artery disease (PAD). People with PAD have blockages in the arteries that slow or stop the flow of blood to the legs. As a result, they have pain and difficulty walking even short distances. It is comparable to angina pectoris for people who have symptomatic heart disease. There are few therapies to treat it.

The first month consisted of weekly in-person visits with the coach. These sessions helped participants learn the difference between high and low intensity walking, allowed them to learn how to use the technology used to control the intensity of their exercise at home, and helped them get started with their exercise activity. The program then consisted of phone calls and remote monitoring by a trainer.

The remote monitoring aspect is important, McDermott said. Although supervised exercise is covered by Medicare and other insurance companies, most people with PAD do not participate in supervised exercise due to the burden associated with traveling three times a week to the medical center to participate.

For the study, 305 people with peripheral artery disease at four medical centers were randomly assigned to high-intensity exercise, low-intensity exercise, or a control group that received phone calls that were unrelated to exercise. Those randomized to an exercise intervention were asked to walk for up to 50 minutes per session, five days a week. Those with high intensity were asked to walk at a pace fast enough to provoke ischemic symptoms in the legs during exercise. Those randomized to low intensity were asked to walk at a comfortable pace that did not induce ischemic symptoms in the legs.

Intensity was remotely monitored by an ActiGraph activity monitor that the participants wore during exercise. This data was uploaded to the study website and viewed by the study advisors. The six-minute walk, treadmill test, and patient-reported outcomes were measured at baseline and at 12-month follow-up.

Patients who participated in high intensity walking exercises significantly improved the distance they could walk in six minutes compared to the low intensity group or the control group. The high-intensity exercise group also significantly improved the amount of time they were able to walk on the treadmill at the end of the study, compared to each of the other two groups.

“PAD patients should be advised to walk for exercise at a pace that induces ischemic symptoms in the legs for benefit,” McDermott said. “Exercise is the most effective non-invasive therapy for improving gait in people with PAD.”

The next step in the research is to determine the biological explanation for the finding that lower extremity ischemia appears necessary to benefit from walking exercise in people with PAD.

Walking can relieve leg pain in people with peripheral artery disease

More information:
Tian L et al. Effect of low intensity versus high intensity home walking on walking distance in patients with peripheral arterial disease: LITE randomized clinical trial. JAMA. 2021; 325 (13): 1266-1276. DOI: 10.1001 / jama.2021.2536

Provided by Northwestern University

Citation: No Pain, No Gain in Exercise for Peripheral Arterial Disease (2021, April 6) Retrieved April 7, 2021 from -disease.html

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