Home Exercise for Leg PAD Patients: ‘No Pain, No Gain’

People with lower extremity peripheral artery disease (PAD) needed exercise training to be intense and painful in order to improve their walking, according to a post-hoc analysis of the LITE trial.

Home-based walking exercise conferred several benefits over the course of a year when conducted at a faster pace to induce ischemic leg symptoms vs slower for a less painful experience:

• Usual walking velocity over 4 m improved by 0.056 m/s (0.125 mph, P<0.01) at 6 months and 0.084 m/s (0.188 mph, P<0.01) at 12 months

• Fast-paced walking velocity over 4 m improved by 0.05 m/s at 6 months (0.11 mph, P=0.03) with no significant effect at 12 months

• Short Physical Performance Battery (SPPB) scores did not change at 6 months, but improved at 12-month follow-up

“This finding is consistent with ‘no pain, no gain’ with regard to walking exercise in PAD,” said Mary McDermott, MD, of Northwestern University Feinberg School of Medicine in Chicago, in a press release about the study in the Journal of the American Heart Association.

“We were surprised by the results because walking for exercise at a pace that induces pain in the legs among people with PAD has been thought to be associated with damage to leg muscles,” McDermott said. “Based on these results, clinicians should advise patients to walk for exercise at a pace that induces leg discomfort, instead of at a comfortable pace without pain.”

An estimated 8 to 10 million people have PAD in the U.S., resulting in approximately 150,000 nontraumatic leg amputations per year.

The primary analysis of the LITE trial had shown that walking exercise at a pace inducing ischemic leg symptoms improved 6-minute walk distance over a pace that did not induce ischemic leg symptoms and compared with controls who did not exercise.

Yet the low-intensity exercise group spent more minutes and days walking during the course of the study, McDermott’s team found.

Thus, the data support the “hypothesis that walking for exercise at a pace inducing ischemic leg symptoms is more important than walking for exercise more frequently or for a longer duration. On the basis of data reported herein, participants with PAD should not be advised to walk for exercise at a pace without ischemic leg symptoms,” the authors concluded.

“Exercise that induces leg pain is beneficial, though difficult,” McDermott acknowledged. “We now are working to identify interventions that can make the higher intensity exercise easier — and still beneficial — for people with PAD.”

She and her colleagues had conducted a post-hoc analysis of LITE, a trial conducted at four medical centers recruiting PAD patients from September 2015 to December 2019.

Individuals were randomized to one of the three study arms (home-based exercise inducing ischemic leg symptoms, exercise inducing no symptoms, or nonexercise) for 12 months. In the exercise groups, participants were asked to walk for exercise at home for 5 days per week, working up to 50 minutes of exercise per session. They were coached weekly in person in the first month of the study, then thereafter by phone.

Out of 305 people randomized, 264 had sufficient data and were included in the present analysis. Mean age was 70 years, and 48% of the cohort were women. Black people comprised 61% of the group.

The SPPB consisted of 4-m walking speed, strength for a chair rise, and balance tests.

By walking speeds and the SPPB, the low-intensity exercise group fared no better than the control group — even numerically doing worse at 12 months, according to the report by McDermott and colleagues.

“Walking exercise at a comfortable pace could potentially have adverse effects on walking speed or the SPPB if participants slowed their walking speed during daily life in response to the exercise intervention, in which they were instructed to walk at a pace without ischemic leg symptoms,” the team surmised.

“However, because the nonexercise control group was not asked to walk for exercise, the control group would not have voluntarily slowed its walking speed, which may explain why the nonexercise control group was significantly worse for a smaller number of outcomes than the group who walked for exercise at a comfortable pace,” the researchers said.

They cautioned that this was a post-hoc analysis with no formal adjustment for multiple testing, and that the results may not be generalizable to supervised treadmill exercise interventions.