When people think about heart health, preventing a heart attack is usually top of mind. But often, the warning signs begin with lesser-known conditions like peripheral artery disease (PAD), a narrowing of the arteries caused by cholesterol buildup. PAD increases the risk of heart attack, stroke, and other serious cardiovascular problems. One subtle sign of PAD may appear in your toenails.

The UK’s NHS says brittle, slow-growing toenails can indicate poor blood flow caused by narrowed arteries. Because capillaries beneath the nail bed need oxygen-rich blood for growth, reduced circulation can slow nail growth and change nail texture or color. Other symptoms include leg cramps while walking, stabbing leg pain, numbness or weakness, shiny skin, hair loss on the legs and feet, and slow-healing sores.

In severe cases, PAD can progress to critical limb ischemia, which may lead to non-healing wounds and even amputation. If you notice symptoms, doctors may use an ankle-brachial index to compare blood pressure in your arms and ankles, or perform imaging tests. Treatments range from medications like aspirin to surgery in severe cases.

Managing risk factors is key: control diabetes, high cholesterol, and blood pressure, maintain a healthy weight, and quit smoking. According to the American College of Cardiology, up to 80 percent of PAD patients are current or former smokers.