You might not spend much time thinking about blood clot symptoms. But since an average of 274 people in the U.S. die from clots every day, it's a good idea to know the signs, and what to do if you encounter them.

What Causes a Blood Clot to Form?

Blood clots form when blood thickens into a semi-solid material. They occur naturally as part of your body's healing process when you get injured. They stop you from bleeding to death, which is awesome.

But clots can also form inside major blood vessels, and that can be a big problem. A clot that grows in a large vein is called a deep vein thrombosis. If it stays in one place, it may not cause you any harm. But if it gets dislodged and flows through the vein to your lungs, it's then called a pulmonary embolism, which can be life-threatening.

So what causes these dangerous clots? Here are some of the risk factors:

• Regularly sitting or standing too long in one position for many hours

• Traveling by car or plane — long hours sitting still can be deadly

• Other extended times without much movement, such as a hospital stay

• Being overweight, which puts pressure on your veins

• Family history of harmful clots or genetically inheriting a blood clotting disorder

• Taking birth control pills or using hormone replacement therapies

• Pregnancy, which increases pressure in the pelvis and legs

• Physical trauma like an assault or a car accident, or even surgery

• Smoking, which affects circulation and clotting

• Age — risk goes up as we age, especially after 60

• Cancer — some types of cancer, as well as some cancer treatments, can potentially increase blood clots

This list is not comprehensive, and roughly 30% of cases are "unprovoked" or occurring without any known risk factors involved.

Blood Clot Symptoms (And What To Do About Them)

So now that you know some of the possible causes, let's talk about what to look for, so you can avoid being one of the 30-40% of cases that go unnoticed.

Common symptoms of leg blood clots include:

• Pain which may feel like a cramp or a Charley horse.

• Areas that are warm or tender to touch

• Swelling

• Redness or discoloration

You may have experienced a Charley horse after playing basketball with your buddies, or maybe you noticed some swelling after sitting all day at your desk. Don't discount the possibility that you may have developed a clot in your leg.

If you have any of these symptoms, talk to your doctor. They can run a variety of tests to determine if you have a clot and what type it might be.

A simple blood test can rule out clots, or an ultrasound can provide a picture of what is going on in your veins. Other tests, such as a CT scan, MRA, or V/Q scan, may be used as well.

If a clot shows up in your test results, your doctor may prescribe blood thinners (anticoagulants) to prevent further clots from forming. You may also need to wear compression socks that fit tightly over your legs to reduce swelling. Surgery can also be required in some cases.

If a clot goes unnoticed, it can move toward your lungs, heart, or brain and cause severe damage. Signs of clots in these areas include:

• Lungs - chest pain, difficulty breathing, and in some cases coughing up blood

• Heart - intense chest pain, left arm pain, shortness of breath, and sudden sweating

• Brain (stroke) - various symptoms including seizures or losing the ability to move or speak (depends on the part of the brain affected)

These are serious medical conditions that can have a major impact on your life (if you survive), so let's look at some ways to lower your risk.

How to Reduce Your Risk of Blood Clots

1. First, avoid sitting or standing for long periods in one position. Switch between sitting and standing throughout the day, and change your posture any time you start to feel uncomfortable. If you have the urge to move, do it!

2. Build movement into your day. When you work in an office, it can be hard to break away from your tasks and get up to move, but it's vital to your health that you do. Exercise regularly, especially if you do sit or stand for long periods for work or travel.

3. When traveling by car, make frequent stops to get out and walk. When traveling by plane, walk the terminals or the cabin. And while you're sitting, move your feet around every 20 or 30 minutes, to keep your blood circulating.

4. Avoid crossing your legs when sitting. When standing, use an anti-fatigue mat to take pressure off your leg muscles and veins.

5. If you have surgery or you're on bed rest, talk to your doctor about moving your legs or feet regularly to help your circulation. And get out of bed and start moving again as soon as possible.

6. Drink plenty of water throughout the day, to help prevent muscle tension and blood vessel constriction. Plus, you'll have to go to the bathroom more, which means you'll be moving more!

7. If you smoke, look into support programs to help you quit. You'll not only reduce your risk of blood clots — you'll save a ton of money and boost your health in lots of other ways.

8. Keep any medical conditions like high blood pressure and diabetes under control.

Be sure to keep a lookout for symptoms of a blood clot, especially if you have any of the common risk factors listed above. Don't discount them — when you get a Charley horse, it might be more than a cramped muscle!

If you develop chest pain or shortness of breath, get medical help immediately. In the meantime, making changes to your habits now is the best prevention — keep your body moving and your blood pumping!