An estimated 900,000 Americans are affected by blood clots every year, so it makes sense to wonder what a blood clot feels like. Knowing the signs and symptoms could save your life.Blood clots are a normal part of our biology—not all are serious or cause for concern. In fact, you need them to stop bleeding after an injury. But sometimes blood clots happen when they’re not needed, and that can spell trouble—especially if they form in the deep veins near your muscles.
“When blood clots form in this deeper system, they can be painful and very dangerous,” says Luis Navarro, M.D., founder of the Vein Treatment Center in New York City. This kind of clot is called a deep vein thrombosis, or DVT. They’re like roadblocks on your blood highway, causing traffic jams in your circulation and preventing the blood flow that keeps your system up and running. If you feel that you are experiencing a blood clot, seek medical attention right away.
Things can get even more serious if a DVT breaks away from its original spot and travels to your lungs. Then it becomes a pulmonary embolism (PE), a clot that prevents these vital organs from getting the oxygen and blood they need. That can damage your lungs and other organs and may even be fatal.
Some people are more prone to DVT than others, so it’s worth staying on top of any risk factors (more on that below). What’s more, “it’s important to recognize symptoms of a blood clot because they can often be minimal or overlooked,” and getting prompt treatment is key, says Dr. Navarro. Here are the warning signs of a blood clot to watch for, along with what a blood clot feels like, so you can act quickly if one strikes.
What is a blood clot?
A blood clot is a mass or clump of blood that forms in arteries and veins, according to the Cleveland Clinic. Blood clots form in response to trauma to help control bleeding, but they may occur for other reasons (such as certain medical conditions) causing serious health symptoms.
Swelling in one limb
A swollen leg or arm is one of the most common signs of a DVT. “Blood clots can block the healthy flow of blood in the legs, and blood can pool behind the clot causing swelling,” says Dr. Navarro.
It’s normal to overlook leg swelling as a symptom of a DVT if you always get large or stiff legs when you fly or during periods of immobility. But be suspicious if your bloated limb comes on quickly, especially if it shows up with a side of pain.
Leg or arm pain
Usually, DVT pain comes as a combo with other symptoms like swelling or redness, but sometimes it can stand alone.
“Unfortunately, pain from a blood clot can easily be mistaken for a muscle cramp or strain, which is why the issue often goes undiagnosed and is specifically dangerous,” says Dr. Navarro.
DVT pain tends to strike when you’re walking or when you flex your foot upward. If you have a charley horse you can’t seem to shake—especially if the skin near it is warm or discolored—have your doctor take a look.
Redness of skin
While it’s true that a bruise is a type of blood clot, it’s not the kind you have to worry about. Unfortunately, you can’t see a DVT. You might see some bruise-like discoloration, but you’re more likely to see red. A DVT causes redness in the affected limb and makes your arm or leg feel warm to the touch.
Chest pain
A pain in your chest may make you think it’s a heart attack, but it could be a pulmonary embolism. “Both a PE and a heart attack share similar symptoms,” says Dr. Navarro. However, PE pain tends to be sharp and stabbing and feels worse when you take a deep breath.
Heart attack pain often radiates from the upper areas of your body like your shoulders, jaw, or neck. The biggest clue is in your breathing—PE pain gets steadily worse with every breath you take. Either way, you need help immediately, so call 911.
Shortness of breath
A blood clot in your lung slows your oxygen flow, and that can leave you feeling winded. “You often won’t have the stamina or breath to make it up stairs. You feel lousy,” says George P. Teitelbaum, M.D., interventional neuroradiologist and director of the Stroke & Aneurysm Center at Providence Saint John’s Health Center in Santa Monica, CA. Get help quickly, especially if this comes on suddenly.
Unexplained cough
Can’t stop hacking? If you’re also having shortness of breath, fast heart rate, or chest pain, it could be a PE. “The cough will be dry, but sometimes people can cough up mucus and/or blood,” says Dr. Navarro. When in doubt, phone your doc or go straight to the ER.
A racing heart
When oxygen is low, your heart rate goes high to try to make up for the shortage. Feeling a flutter in your chest and having trouble with deep breaths could be your body sending out an SOS that you’ve got a PE lurking in your lungs, Dr. Teitelbaum says.
“For a small blood clot, the heart rate rises in part due to chest pain, shortness of breath, and the related anxiety that these cause,” says Lewis Nelson, M.D., chair of the department of emergency medicine at Rutgers New Jersey Medical School. There is also a release of chemicals from lung tissues that leads to a rise in heart rate.
If the clot is larger, it can cause a reduction in blood oxygen content “and even changes in blood flow that lead to a compensatory rise in heart rate,” Dr. Nelson says.
Feeling faint
“The lightheadedness is due in part to the chemical released from the lungs, changes in oxygenation of the blood, and in the blood pressure and heart rate,” Dr. Nelson says. “The brain is sensitive to changes in oxygen and to changes in blood flow.”
While it’s not an overly common symptom of a blood clot, it happens enough. One study published in the New England Journal of Medicine found that pulmonary embolisms were responsible for about 17% of hospitalizations for fainting in the 560 older people who were studied.
Blood clot in leg symptoms
Blood clots in the leg are “usually felt in the calf,” says Erin McNeely, M.D., an internal medicine physician at Corewell Health. “There is a tightness or even ropiness in the area [and] there can be redness and tenderness with pressing into the meat of the calf,” she says.
The most common symptoms a person may experience, according to Joshua Kra, M.D., assistant professor of medicine in the Division of Hematology/Oncology at Rutgers New Jersey Medical School, include:
Pain in the leg
Swelling of the leg
Warmth
Redness of the affected leg
Symptoms are usually linked to the size of the clot, Dr. McNeely says. “A small enough clot might not show any symptoms,” she points out. Another thing to keep in mind, per Dr. McNeely: “Clots are almost always on one side; symptoms on both sides are almost never blot clot related.”
Pain from a blood clot will also be persistent—meaning, it won’t come and go, Dr. McNeely says.
DVT pain tends to strike when you’re walking or when you flex your foot upward. If you have a Charley horse you can’t seem to shake—especially if the skin near it is warm or discolored—have your doctor take a look.
Blood clot in arm symptoms
Dr. McNeely says that deep vein clots in the arms are “much less common” than those in the legs, but they can happen. She says signs may include:
Tenderness
Swelling
Redness
Ropey feeling over the vein
Like a blood clot in your leg, the pain will be pretty constant, Dr. McNeely says. A blood clot in the arm may also cause “severe pain and swelling,” Dr. Kra says.
What does a blood clot in the lung/chest feel like?
A blood clot in the chest area refers to a pulmonary embolism (a blood clot in the lung) or coronary thrombosis (a blood clot in the heart).
A pulmonary embolism can often feel like a heart attack, or can feel like a sharp and stabbing pain that gets worse with deep breaths, per Dr. Navarro.
Coronary thrombosis symptoms, per Yale Medicine, include:
Severe pain in the chest and arms
Sweating
Trouble breathing
Blood clot risk factors
Anyone can get a blood clot, but there are some factors and health conditions that may raise your risk of developing a blood clot, according to Medline Plus and Penn Medicine:
Atherosclerosis
Atrial fibrillation
Cancer and cancer treatments
Certain genetic disorders
Certain surgeries
COVID-19
Diabetes
Family history of blood clots
Overweight and obesity
Pregnancy and giving birth
Serious injuries
Some medicines, including birth control pills
Smoking
Staying in one position for a long time, like being in the hospital or taking a long car or plane ride
Hormone-replacement therapy
What to do if you think you have a blood clot
“It depends on how sick you feel,” Dr. Teitelbaum says. If you’re having shortness of breath and no energy and this is unusual for you, call 911 immediately. “You need to go to the emergency room and be evaluated,” he says. But if you have leg tenderness or swelling and you’re not sure what’s going on, it’s okay to call your doctor about next steps.
Treatment usually includes blood-thinning medications, per the American Heart Association (AHA). Those can generally be broken down into anticoagulants, which are tablets or injectables that help prevent blood clots, and thrombolytic therapy, which involves taking medication to dissolve clots. These can be given through an arm vein or by inserting catheters into the clot in the vein or lung. In more severe cases, you may need surgery.
Just know that treatment doesn’t end once the blood clot is gone. “If you have a blood clot, you may need to continue to take anti-coagulants for a few months afterward,” Dr. Teitelbaum says.
How to lower your risk of developing a blood clot
Sometimes blood clots just happen, but there are a few things you can do to lower the risk you’ll experience one. According to Medline Plus, those include:
Moving around as soon as possible after you’ve been laid up with a surgery, illness, or injury
Moving around every few hours when you have to sit for long periods of time, like on a long flight or road trip
Exercising regularly
Avoiding smoking
Maintaining a healthy weight
When to see your doctor
As Dr. Teitelbaum explained, if you are experiencing an unusual bout of intense fatigue and shortness of breath, you should call 911 immediately and get to an emergency room as soon as possible.
However, if you are experiencing other symptoms (such as soreness, tenderness, or swelling) an emergency visit may not be necessary—but you should certainly call your doctor for medical advice.
Additionally, if you have a number of blood clot risk factors it might be a good idea to schedule a visit with your doctor to discuss lowering your risk.