Researchers at Northwestern University's Feinberg School of Medicine in Chicago found that people with peripheral arterial disease (PAD) who walked at a pace that caused discomfort or even pain improved their ability to walk.

PAD occurs when the arteries that carry blood from the heart throughout the body narrow, reducing the flow of blood and oxygen. This can cause cramps, weakness, fatigue, aching and pain in the legs and feet when walking. Symptoms resolve after about 10 minutes of rest.

The new study, published in the Journal of the American Heart Association, involved 264 people with PAD, who were divided into three groups. The average age of the participants was 69 years.

For 12 months, the first group walked at home at a comfortable pace. The second group walked at a pace that produced leg symptoms. The third group did not walk.

The study found that after 12 months, people who raced walking to pain or discomfort in their legs scored nearly one point higher on three leg function tests than people who walked at a comfortable pace without leg pain.

Those who walked at a comfortable pace did not improve in walking speed at either six or 12 months compared to those who did not walk.