That phrase "no pain, no gain" might truly apply to people with peripheral artery disease (PAD), a new study finds.
Researchers found that people with PAD who walked at pace that caused discomfort or even pain improved their walking ability.
"Exercise that induces leg pain is beneficial, though difficult," said senior author Dr. Mary McDermott, a professor at Northwestern University Feinberg School of Medicine in Chicago.
"We now are working to identify interventions that can make the higher intensity exercise easier -- and still beneficial -- for people with PAD," she said.
PAD occurs when the arteries that transport blood from the heart throughout the body narrow, reducing blood and oxygen flow. It can cause cramping, weakness, fatigue, and aching and pain in the legs and feet while walking. Symptoms subside after about 10 minutes of rest.
While researchers knew that walking on a treadmill helped improve how well and how far a person with PAD could walk, they didn't know what difference pace would make.
The new study, published July 27 in the Journal of the American Heart Association, included 264 people with PAD who were randomly assigned to one of three groups. They were participants in a trial called Low-Intensity Exercise Intervention in PAD (LITE) that included 305 people at four U.S. universities.
For 12 months, the first group walked at home at a comfortable pace. The second group walked at a pace that induced leg symptoms. The third group did not walk for exercise. The exercising groups wore a device to monitor their walking intensity and time.
A threshold for high or low intensity was determined for each exercising person. Patients uploaded data on exercise frequency, intensity and duration to a study website.
Participants completed leg function tests at the outset and again at six and 12 months. These measured how quickly they walked 13 feet at their usual pace and as fast as they could go. They also completed a short physical performance test that included walking at their preferred speed, a standing balance test and chair rises.
Participants in the fast-walking group were able to go 11 feet per minute faster at six months and 16 feet per minute faster at 12 months than those who walked at low intensity. They were nearly 13 feet per minute faster than the non-walkers at six months. This increase was not statistically significant at one year.
At 12 months, the people who walked for exercise with leg pain or discomfort totaled almost one point higher on the three leg function tests than people who walked at a comfortable pace without leg pain, the study found.
Those who walked for exercise at a comfortable pace had no improvement in walking speed at six or 12 months compared to non-walkers.
“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 in a journal news release.
"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," she said.
Participants' average age was 69.
Between 9 million and 10 million Americans have PAD, and Black people, American Indians and the poor are disproportionately affected. About 150,000 people a year have amputations because of the condition.
Researchers said their findings must be confirmed in future studies and results from walking at home may differ from those obtained while walking on a treadmill under professional supervision.
The American Heart Association and 24 collaborators launched the PAD National Action Plan in May, to help prevent PAD complications, address heart health risks and improve of quality of life for those with the disease.
The U.S. Centers for Disease Control and Prevention has more on peripheral artery disease.
SOURCE: Journal of the American Heart Association, news release, July 27, 2022