The day this article was written was also the day of the Hong Kong Marathon. Although it was raining heavily, the streets in the morning were still full of runners in sportswear. Even soaked through, they radiated the energy and pleasure associated with good health.

Running is well known to improve physical fitness, but it may also be used as part of treatment for some illnesses. Among vascular conditions, peripheral arterial disease is one of the areas in which exercise therapy is relatively common and supported by a considerable body of medical literature.

Peripheral vascular disease most commonly affects the arteries of the lower limbs. Atherosclerosis causes the vessel wall to thicken, the artery to narrow, and sometimes even to become occluded, reducing blood flow to the legs. A common symptom is numbness, weakness, or aching in the calf after walking for a period of time, followed by the need to stop and rest before the pain eases. The walking distance may range from a few dozen to a few hundred metres, depending on disease severity. Medically, this is known as intermittent claudication.

The natural response for many people is to walk less in order to avoid pain. In fact, that may not help and may even contribute to muscle wasting in the lower limbs, making walking progressively more difficult.

By contrast, medicine has found that when patients follow a structured exercise programme and maintain an appropriate amount of daily walking, the distance they can walk often becomes longer and the pain may become less severe. Exercise does not reopen arteries that are already narrowed or blocked, but it may help small collateral vessels widen so that blood can bypass the obstructed artery and continue supplying the leg muscles. It may also help preserve muscle health and reduce deconditioning. Many patients experience meaningful symptom improvement after exercise therapy, and structured walking programmes are widely used as part of standard management for intermittent claudication. In some patients with a good response, this may reduce the need for surgery.

Author: Honorary Clinical Associate Professor, Department of Surgery, The University of Hong Kong; President, Vascular Health Foundation