An estimated 30,000 Australians are affected by harmful 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 vascular specialist Dr Luis Navarro. 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 recognise 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. 

Signs of a blood clot

1. 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.

2. 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 muscle spasm you can’t seem to shake, especially if the skin near it is warm or discoloured, have your doctor take a look.

3. Redness on your skin

While it’s true that a bruise is a type of blood clot, it’s not the kind you have to worry about. You can’t see a DVT. You might see some bruise-like discolouration, 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.

4. Chest pain

A pain in your chest may make you think 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 worst when you take a deep breath.

Heart attack pain often radiates from 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 000.

5. 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 interventional neuroradiologist Dr George Teitelbaum.

Get help quickly, especially if this comes on suddenly.

6. 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.

7. 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 Dr Lewis Nelson, MD, 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.

8. 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 hospitalisations for fainting in the 560 older people who were studied.

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 000 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, reports 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 000 immediately and get to an emergency room as soon as possible.

However, if you are only 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.

© prevention.com