How to Spot a Blood Clot in Your Legs and Improve Your Circulation

Deep vein thrombosis (DVT), a condition that causes a clot in a vein (often in your legs), can sometimes develop without warning—especially when you’re traveling or seated for long stretches at a time. But being able to recognize deep vein thrombosis symptoms can potentially save your life. Read on to learn the signs to watch for, common risk factors and simple preventive measures you can take to reduce your risk.

What is DVT?

“Deep vein thrombosis is when a blood clot forms in one of the deeper veins in the body, typically in the big veins in your calves or thighs,” says vascular surgeon Anahita Dua, MD, an associate professor of surgery at Harvard Medical School and director of the Vascular Lab at Massachusetts General Hospital in Boston, MA. However, DVT can also occur in deep veins located in the arms, neck, brain or abdomen, according to the International Society on Thrombosis and Haemostasis. 

When your blood is flowing properly, your arteries carry the blood your heart pumps out to different areas in the body, says Dr. Dua. Once the blood gets to where it needs to be, your veins transfer it right back to your heart.

But when blood flow slows down, the linings of the blood vessels are damaged or blood becomes more “sticky,” a clot can form. And, If there’s a big enough blood clot sitting in a deep vein, it can block off blood flow to the heart, Dr. Dua explains.

When deep vein thrombosis is an emergency

DVT has the potential to be dangerous if a part of the main blood clot breaks free and travels north. “These pieces can travel through the bloodstream up to the lung,” says Mary Cushman, MD, a hematologist, professor of medicine and pathology at the University of Vermont Larner College of Medicine in Burlington, VT. “When this occurs, it’s called a pulmonary embolism (PE).”

What makes a pulmonary embolism potentially life-threatening is that if a piece of the clot is big enough, it can get lodged in the lungs, blocking a person’s ability to breathe. Besides shortness of breath or difficulty breathing, a PE can cause the following symptoms: 

• Chest pain or discomfort that typically worsens with coughing or breathing

• Cough or coughing up blood

• Lightheadedness, very low blood pressure or fainting

• An irregular or faster-than-normal heartbeat (i.e. more than 100 beats per minute when at rest)

“Anyone experiencing dramatic symptoms should go to the emergency room,” stresses Dr. Cushman, who is also the medical director of the Thrombosis and Hemostasis Program at the University of Vermont Medical Center. And while a pulmonary embolism can be life-threatening, it’s important to know survival rates are high, according to the Centers for Disease Control and Prevention (CDC).

Deep vein thrombosis symptoms

Fortunately, early detection of deep vein thrombosis can prevent a pulmonary embolism, notes Dr. Cushman. Since this condition can be a medical emergency, it’s important to be aware of common DVT symptoms in your legs and alert your doctor if you notice the following:

• Swelling

• Unusual pain

• Tenderness

• Red or discolored skin 

• Warmth in the area 

Dr. Cushman says with deep vein thrombosis, you also don’t have to have all the symptoms. “There can be aching but no swelling, and vice versa,” she says. You can also have no symptoms at all. 

In fact, the CDC reports about half of people with deep vein thrombosis are asymptomatic. That’s why knowing the risk factors for DVT (more on that below) is vital when it comes to prevention.

Who’s at risk for deep vein thrombosis?

Anyone can suffer from DVT, but there are certain things that can make blood thicker and more likely to clot, says Dr. Dua. Here, common factors that can increase your risk of deep vein thrombosis:  

• Sitting for an extended time (4 hours or more), such as when traveling

• Having varicose veins

• Smoking 

• Obesity

• A family history of DVT or having a clot in the past

• Hormone replacement therapy

• Being 60 or older

• Prolonged periods of inactivity, such as after surgery or a hospital stay

• Having cancer and/or undergoing chemotherapy

How to prevent deep vein thrombosis

While DVT can be scary, the good news is that there are several easy things you can do to reduce your risk of the condition and ward off clots in the long term.

Slip on socks

Compression socks or stockings hug your calves in a way that encourages blood flow in the legs. One study in The Lancet found compression socks curb the risk of DVT by 63 percent. 

“The stockings keep the blood moving along because the stockings compress the vein and hold it in place, so the blood can’t balloon outwards,” says Dr. Dua.

Compression stockings come in three levels of pressure: Low, medium and high. Dr. Dua typically recommends medium-pressure socks to her patients. “This level is just enough compression to push the blood along, but if those are uncomfortable, you can absolutely wear the low-pressure ones.” 

Sip some water

A study in the British Journal of Haematology suggests staying well hydrated reduces the risk of DVT by as much as 47 percent. The reason? “If you’re dehydrated, your blood gets thicker,” says Dr. Dua. 

Water keeps your blood thinner and easier to travel through your veins. Most experts recommend aiming to drink at least 8 ounces every two hours, especially if you’re traveling.  

Take a short stroll 

Walking around, even if it’s just a few minutes, can be beneficial when it comes to warding off deep vein thrombosis. “With every step, you’re pumping your calf muscles, allowing blood to push upwards a few centimeters,” says Dr. Dua. This is what you want because when you’re not moving, blood stagnates and this can result in a clot, she adds.

Getting up and walking is especially important if you’re sitting on a plane or train for long periods. Dr. Cushing suggests if you’re stuck sitting for more than two hours, take a few minutes to walk up and down the aisle and stretch. And if you can find enough room, perhaps by the lavatory (or inside one!), do a few deep knee bends or squats. 

Lift your heels

If you’re stuck sitting and aren’t able to get up and walk, Dr. Dua says you can exercise your calves and feet by doing several reps of lifting your heels so you’re on your tiptoes, circling your ankles and flexing your knee back and forth. Dr. Dua suggests alternating all three exercises over five to seven minutes. Try 30 to 45 seconds for each exercise, then repeat. 

You can find more leg exercises to help prevent DVT in the video below: 

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This content is not a substitute for professional medical advice or diagnosis. Always consult your physician before pursuing any treatment plan.