Peripheral artery disease (PAD) is a condition where the arteries that carry blood to your legs become narrowed or blocked, reducing circulation to your lower limbs. It affects roughly 113 million people worldwide, and the number of cases has doubled since 1990. Most people first notice it as leg pain during walking that goes away with rest, but PAD can progress silently and lead to serious complications if left unmanaged.
How PAD Develops
PAD is caused by atherosclerosis, the same process that narrows arteries in the heart. It starts when cholesterol particles get trapped in the walls of your arteries. Once there, these fats become oxidized and trigger an inflammatory response. Immune cells rush to the area, absorb the oxidized fats, and form what are called foam cells. Over time, these foam cells accumulate into plaque that bulges inward and narrows the artery.
The process is made worse by oxidative stress, a chemical imbalance that damages the inner lining of blood vessels. When that lining is damaged, the artery loses its ability to relax properly, which compounds the narrowing effect. In addition, the smooth muscle cells in the artery wall can transform into bone-like cells, causing the artery to stiffen and calcify. In the smaller arteries below the knee, blood clots can also contribute to blockages. Research published in American Heart Association journals found that in arteries below the knee with significant narrowing, less than half had substantial plaque buildup. In many cases, blood clots were the primary cause of the obstruction.
What PAD Feels Like
The hallmark symptom is called intermittent claudication: a dull, aching pain in your legs that comes on during walking and fades within a few minutes of rest. Many people describe it as a deep muscle cramp, similar to a charley horse. It most commonly hits the calves but can also affect the thighs or buttocks, depending on where the artery is narrowed. Some people feel less of a sharp pain and more of a heavy tiredness in their legs, as if the muscles are giving out.
Numbness or tingling can accompany the pain because nearby nerves are also starved of blood flow. As PAD progresses, you may notice that one foot feels noticeably colder than the other, or that the skin on your lower legs looks shiny or changes color. Hair loss on the legs and slow-growing toenails are other subtle signs of reduced circulation.
A significant number of people with PAD have no symptoms at all, which is one reason it often goes undiagnosed until the disease is more advanced.
PAD vs. Venous Insufficiency
Leg pain from PAD is easy to confuse with venous insufficiency, a condition where blood pools in your leg veins instead of flowing back to the heart. The key difference is timing. PAD pain shows up during activity and improves with rest. Venous insufficiency causes a persistent heaviness or aching that worsens after long periods of standing or sitting. Swelling is more prominent with venous problems, while coldness in the foot or lower leg points more toward PAD. Both conditions can cause skin changes and ulcers over time, but they require very different treatment approaches.
Who Is Most at Risk
Smoking and diabetes are the two strongest risk factors. In one large study tracking participants over six years, people who developed diabetes were more than twice as likely to develop PAD compared to those with normal blood sugar. Current smokers had about 60% higher odds of developing the disease after accounting for other risk factors like cholesterol and waist circumference.
High blood pressure adds further risk, particularly when systolic pressure (the top number) exceeds 135 mmHg. High cholesterol fuels the plaque-building process directly. Age is also a major factor: PAD becomes significantly more common after 50, and the risk climbs with each decade. A family history of heart disease or stroke increases your likelihood as well, since PAD shares the same underlying process as coronary artery disease.
How PAD Is Diagnosed
The primary screening tool is the ankle-brachial index (ABI), a painless test that compares blood pressure readings at your ankle and your arm. A normal ABI falls between 1.00 and 1.40. Scores between 0.91 and 1.00 are considered borderline. A score of 0.90 or below confirms PAD. The lower the number, the more severe the blockage. An ABI below 0.50 signals significantly restricted blood flow and a higher risk of complications, including tissue damage that may not heal.
For people with diabetes, an abnormal ABI carries particular weight. A score of 0.90 or below is associated with an eightfold increase in the seven-year risk of amputation. If the ABI suggests PAD, imaging tests such as ultrasound or CT angiography can pinpoint the exact location and extent of the blockages.
Exercise as a Primary Treatment
Structured walking programs are one of the most effective treatments for PAD symptoms. The standard approach involves supervised sessions three times per week, each lasting about 60 minutes, over a 12-week period. During these sessions, you walk until the pain reaches a moderate to maximum tolerable level, then rest until it subsides, and repeat. This cycle gradually trains your legs to function better with limited blood flow and can stimulate the growth of small collateral blood vessels that bypass the blockages.
Medicare and most commercial insurers cover up to 36 supervised exercise sessions over 12 weeks. If symptoms persist, coverage can extend to another 36 sessions. The improvement in walking distance and quality of life from a structured program often rivals what procedures can achieve for people with moderate symptoms.
Medications That Slow the Disease
PAD treatment focuses on reducing the risk of heart attack, stroke, and worsening leg symptoms, since the same plaque buildup happening in your legs is likely happening in arteries throughout your body. Cholesterol-lowering medications are a cornerstone, with guidelines recommending treatment aggressive enough to cut LDL cholesterol by at least 50%. Blood pressure management targets below 130/80 mmHg.
Blood thinners play an important role in preventing clots from forming at the site of narrowed arteries. Low-dose aspirin is the traditional choice. For people at higher risk, combining a very low dose of a clot-prevention drug with aspirin has been shown to reduce both cardiovascular events and serious limb complications, though this combination is reserved for those who aren’t at elevated risk of bleeding.
Smoking cessation is treated as a medical intervention, not just a lifestyle recommendation. Prescription options that improve quit rates are available and are considered part of standard PAD care. For people with diabetes, newer classes of blood sugar medications have been shown to reduce cardiovascular events specifically in people who also have PAD.
When Procedures Are Needed
If symptoms are severe or don’t improve with exercise and medication, two types of procedures can restore blood flow. Angioplasty involves threading a thin catheter into the blocked artery and inflating a small balloon to open it, often leaving a stent (a tiny mesh tube) to keep it open. Bypass surgery reroutes blood around the blockage using a vein taken from elsewhere in your body.
The choice between the two depends on where the blockage is, how long it is, and your overall health. Shorter blockages in larger arteries tend to respond well to angioplasty with stenting. Longer or more complex blockages, especially below the knee, may benefit more from bypass. For people with diabetes, bypass surgery generally produces better long-term outcomes. Bypasses using veins can start to deteriorate after eight to ten years, at which point stents are typically the preferred option for any needed follow-up work.
What Happens If PAD Progresses
The most advanced stage of PAD is called chronic limb-threatening ischemia (CLTI). At this point, blood flow is so severely restricted that you experience intense pain even at rest, particularly at night or when lying down. Open sores or wounds may develop on your feet or toes that heal extremely slowly or not at all. By definition, these symptoms have been present for more than two weeks.
CLTI is a medical emergency in slow motion. Up to 1 in 3 people diagnosed with CLTI require a major amputation (above the ankle) within one year. Early detection and treatment of PAD is the most effective way to prevent reaching this stage. Paying attention to leg pain during walking, checking your feet regularly if you have diabetes, and addressing risk factors early can make a significant difference in long-term outcomes.