When you think about protecting your heart health, heart attack prevention is probably the first thing that comes to mind. However, the best way to avoid such a catastrophic event is to first prevent the more subtle heart conditions that can lead to one.

One such condition is peripheral artery disease (PAD), a common but serious heart condition that causes arteries to narrow over time. A 2005 study published in the medical journal BMC Cardiovascular Disorders found that 33 percent of PAD patients died within five years of their diagnosis.

That’s exactly why it’s so essential to notice the signs of less-often mentioned heart conditions, particularly PAD. Experts say there’s one specific, little-known symptom you may notice in your toenails that could indicate a problem. Read on to find out what subtle sign you should look out for and what your doctor may recommend you do about it.

If your toenails are brittle and grow slowly, get your heart checked.

Peripheral artery disease (PAD) is a form of cardiovascular disease. It occurs when fatty deposits of cholesterol build up on the inner walls of arteries, a process called atherosclerosis. While not immediately life-threatening, PAD makes you more likely to develop other heart health problems, such as heart attack, stroke, coronary artery disease, and angina, warns the UK’s National Health Service (NHS).

Because PAD most commonly affects the arteries in the legs, many people with the condition notice symptoms in their legs and feet. People with PAD often report having “brittle, slow-growing toenails,” says the NHS.

According to the U.S. Vascular Centers, this occurs because the capillaries located beneath the nail bed need an oxygen-rich blood supply for nails to grow. As blood flow is restricted due to narrowed arteries, toenail growth may slow, and the color and texture of the nails and nail beds may change.

Pay attention to other signs that may indicate PAD

While many people with PAD don’t experience any symptoms, others notice signs of the condition in the lower half of their body. According to the NHS, the most common symptom is a stabbing, intermittent leg pain, which can be mild or severe and affect one or both legs. Many patients also experience cramps that begin in the toes and move up to the calves, especially when walking or doing other physical activity.

In addition to pain and slow toenail growth, patients with PAD also frequently experience hair loss on their legs and feet. Numbness or weakness in the legs, leg and foot ulcers, shiny skin on the lower extremities, and changes in skin color on the legs and erectile dysfunction in men.

The most severe symptoms of PAD may indicate a related condition known as critical limb ischemia. This condition causes blockage of the arteries, severely limiting blood flow to the arms or legs. It can cause pain while sleeping or resting and can lead to open sores or wounds on the toes or legs that do not heal or heal very slowly. If left untreated, this condition can lead to amputation of the affected limb.

The Different Tests Your Doctor May Perform to Detect This Disease

If you notice any of these symptoms, it is crucial to tell your doctor, says the Centers for Disease Control and Prevention (CDC). Your doctor may perform an ankle-brachial index, a noninvasive test that measures blood pressure in your ankles and compares it with blood pressure in your arms at rest and after exercise. Your doctor may also perform imaging tests such as ultrasound, magnetic resonance angiography (MRA), and computed tomography (CT) angiography.

Once your doctor has diagnosed the condition and determined its severity, there may be a variety of possible treatment options available to you. In less severe cases, your doctor may recommend taking a daily aspirin or an antiplatelet medication to increase blood flow and prevent complications related to PAD. In more severe cases, your doctor may recommend surgery to bypass blocked arteries, says the CDC.

On the other hand, manage your risk factors now.

If you suspect you may be developing PAD or any other heart health problem, you should start managing your risk factors today. Primarily, this involves controlling any chronic conditions you may have that make developing PAD more likely, such as diabetes, high cholesterol, high blood pressure, or heart disease. Experts also say that maintaining a healthy weight through diet and exercise can help prevent PAD and minimize its complications.

Finally, studies show that up to 80 percent of people with PAD are current or former smokers, says the American College of Cardiology. If you currently smoke, quitting can greatly reduce your symptoms and risk of complications.