Fitness experts used to stress the benefits of heavy-duty aerobic exercise. But the message changed to moderation after a number of studies showed that physical activity that's far less taxing is associated with lower rates of heart disease, some cancers, and several other illnesses — if it's done regularly. Plain old walking usually tops the moderate-intensity exercise list because it's easy, convenient, and free, and it requires minimal equipment — a comfortable pair of shoes. The trouble is that walking isn't so easy for everyone.
This article looks at three nonarthritic conditions that cause leg pain and may affect walking, and some ways to treat and manage them.
1. Peripheral artery disease
Peripheral artery disease is a form of atherosclerosis. Fat- and cholesterol-filled plaque narrows arteries, and blood clots can collect on the plaque, narrowing them further. In peripheral artery disease, the arteries affected by atherosclerosis tend to be the ones that supply the leg muscles. The classic symptom is cramping, tight pain that's felt in muscles "downstream" from the narrowed artery. It can occur in the buttocks, thigh, calf, or foot, but occurs most often in the calf. The pain tends to come on with walking, get worse until the person stops walking, and go away with rest. Similar to angina, the pain caused by peripheral artery disease comes from working muscle cells that are "starved" for oxygen because of obstructed blood flow.
Signs of peripheral artery disease include a diminished pulse below the narrowed artery, scratches and bruises in the lower leg that won't heal, and pale and cool skin. The diagnosis usually depends on the ankle-brachial index, which compares the blood pressure at the ankle to the blood pressure at the arm.
Researchers have found that tightly structured, supervised exercise programs can help people increase the amount they can walk before the pain kicks in. These programs usually involve walking till it hurts (which may be only for a few minutes), resting till the pain goes away, and then walking again.
Cilostazol (Pletal), a drug that widens blood vessels, and pentoxifylline (Pentoxil, Trental), which decreases the viscosity of blood, can sometimes help improve pain-free walking distance, but both drugs have side effects, so there's a downside that needs to be taken into consideration.
If peripheral artery disease is serious, or isn't improving with exercise and medication, doctors can reopen the blocked artery with angioplasty or use part of a blood vessel from elsewhere in the body to reroute circulation around the blockage. But the track record of these revascularization procedures is mixed, and some studies suggest that the results from a structured exercise program can be as good, or even better.
2. Chronic venous insufficiency
Like peripheral artery disease, chronic venous insufficiency is a condition of poor circulation, but it involves the veins and the blood's return trip back to the heart and lungs.
In people with chronic venous insufficiency, the valves that even out the pressure and keep blood from flowing backward are damaged, so blood tends to pool in the legs and feet instead of traveling "north" to the heart. Symptoms include swelling, inflammation of the skin (dermatitis) and the connective tissue underneath (cellulitis), and ulcerated, open wounds on the bony "bumps" of the ankle. Legs may feel achy or heavy. And when people walk, they may feel a tight, "bursting" pain, most often in the groin or thigh.
The symptoms from a mild case of chronic venous insufficiency can be helped by lying on your back and using a pillow to elevate your legs so blood flows downhill to the heart. If you're sitting for long periods, pointing your toes up and down several times can flex the vein-pumping leg muscles. More serious cases needed to be treated with compression stockings that squeeze harder at the ankle than at the knee. There aren't any medications for chronic venous insufficiency. Surgical treatments are reserved for the most serious cases.
3. Lumbar spinal stenosis
Spinal stenosis can occur anywhere along the spine as a result of the vertebrae, the disks between them, or their supporting structures impinging on the tube-like spinal canal that holds the spinal cord and the roots of the nerves that branch off of it. Pain comes from the mechanical pressure, and perhaps also from the pinching off of the blood supply that nerves need.
When spinal stenosis occurs in the lumbar region, lower back pain can be a symptom but often it's the legs that are affected. The pain can resemble the pain caused by peripheral artery disease: cramping tightness that increases with walking, although it's often felt in the thigh rather than the calf. The legs may also feel weak and numb.
The diagnosis starts with discussion of symptoms and medical history. One important clue is whether the pain eases when the back is curved forward, or flexed. That posture tends to take pressure off the lumbar region.
An MRI or CT scan will often be ordered to confirm a diagnosis, but imaging studies shouldn't be used to make one. Many people have spinal stenosis that shows up on an imaging study but doesn't cause any symptoms.
Treatment usually begins with physical therapy and exercises aimed at strengthening back and abdominal muscles. Pain relievers may help. Growing numbers of older patients are getting corticosteroid injections into the spine. If the pain persists, surgery is an option.
August 2008 update