For people with peripheral artery disease (PAD), even short walks can be exercises in excruciation.
But a new study published in the Journal of the American Heart Association has found that patients who can push through the pain appear to reap significant benefits in ambulation, balance, and leg strength, which have been linked to increased longevity.
“You have to push yourself and get those uncomfortable symptoms, or else you probably won’t get gains,” said Mary McDermott, MD, professor of medicine at Northwestern University, Chicago, and the senior author of the study.
Walking for exercise is critical for people with lower-extremity PAD, Dr. McDermott said, but leg pain dissuades many people with the condition from doing so. She said her group hopes that showing the payoff of the “no pain, no gain” approach gives people with PAD the resolve to walk regularly, even when it’s hard.
The new study, a post hoc analysis of the LITE (Low-Intensity Exercise Intervention in PAD) trial, found that low-intensity exercise did not improve the symptoms of PAD but high-intensity exercise did.
Dr. McDermott and her colleagues compared 109 people with PAD who walked fast enough to cause discomfort versus 101 people who walked at a comfortable pace and 54 people who did not exercise at all. The average age was 69 years, 48% of participants were women, and 61% were Black.
Everyone in the exercise groups walked at home, with visits to a medical center early in the study to get exercise tips and then phone support from exercise coaches throughout the remainder of the study. Researchers encouraged those in the discomfort group to walk fast enough to cause significant pain in their legs, for up to 10 minutes or as long as they could. They then rested before walking again, ideally up to five times per day for 5 days per week.
At 6 months, people in the discomfort group were walking 0.056 m/sec faster than those in the comfort group during a 4-meter walking test (95% confidence interval [CI], 0.19-0.094 m/sec; P < .01), a gap that had grown by 12 months to 0.084 m/sec (95% CI, 0.049-0.120 m/sec; P <.01), according to the researchers. A statistically significant gap also emerged between the discomfort and nonexercising group at 6 months, but it eventually closed.
“It’s a question that people have asked for some time: Is it necessary to get that ischemic pain when you walk?” Dr. McDermott said. “This is the first well-powered clinical trial to provide a definitive answer on that, and the answer is that you do need that discomfort. It wasn’t even close.” Indeed, Dr. McDermott said, it’s possible that walking merely to the point of comfort and never pushing beyond it may harm people with PAD.
At the 6-month mark, the researchers found no statistical difference between the discomfort and comfort groups on a cumulative scale of usual walking speed, ability to rise from a chair, and ability to maintain balance in several positions. By 12 months, the two groups had diverged, with the discomfort group improving by almost 1 point on the scale, whereas the performance of the comfort group declined. No significant differences emerged between the discomfort and nonexercising groups, the researchers reported.
The investigators found, counterintuitively, that some people in the study who did not record exercising did as well as those in the discomfort group,
Dr. McDermott noted that the nonexercise group was smaller than the discomfort group, making firm comparisons between the two challenging to draw. In addition, people whose exercise was not recorded were not asked to take it easy whenever they walked, unlike those in the comfort group. As a result, she said, some people in this group may have walked vigorously.
Dr. McDermott emphasized that these benefits occurred at home rather than at medical centers that can be difficult for some people to visit regularly.
“It’s always good to have this kind of information for patients, to show them that it’s possible for them to continue to improve,” said Jonathan Ehrman, PhD, associate director of preventive cardiology at Henry Ford Medical Center, Detroit. Dr. Ehrman was not involved in this study but said that he is contemplating running a similar home-based study that would use video rather than telephone support for patients.
“There’s emerging data about walking speed being related to longevity and predicting better outcomes in cardiac surgeries,” Dr. Ehrman said. “It seems to be, if you can get people walking faster or they have a better walking pace, related to better health outcomes.”
Dr. McDermott reported relationships with Regeneron, Helixmith, Mars, ArtAssist, ReserveAge, and Hershey. Dr. Ehrman reported no relevant financial conflicts of interest.
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