ROCKFORD, Ill. (WTVO) — March is “National Blood Clot Awareness Month,” a growing health issue that affects nearly a million Americans a year.

They are actually a normal response to an injury where a blood vessel gets broken. A person will continue to bleed if it does not clot, causing a hemorrhage.

The problem is that they can cause a heart attack if it occurs for the wrong reason.

“Either you really got into a movie marathon or you’re on a plane to Hawaii or something like that, or a long car ride,” said Dr. Mark Meeker, physician and vice president of community medicine at OSF Healthcare. “Some people get in the car and they drive for hours, they don’t take a break to go for a small walk.”

Blood clots result in about 100,000 deaths each year. Blood is always flowing through the body, but Meeker said that there could be a bigger problem if something changes that flow.

“If you think about if you mix cocoa and milk, and you stir it, it all dissolves. If you just dump it in there, it clumps up, so if our blood isn’t flowing, it can tend to clump or clot,” Meeker said. “If a blood clot breaks off and goes to my heart or lungs, that’s called a pulmonary embolus. That’s very serious and can be life threatening.”

There are signs to look out for, which vary depending on where the clot is located and what it is affecting.

“Big swollen leg with discomfort, the discoloration is not normal,” Meeker said. “If you have one leg swollen and not the other and you’ve either had recent surgery or a recent illness, or you are sitting for a long period of time unusually.”

Some risk factors include smoking or taking birth control pills, but Meeker warned that this is a problem that can happen to anyone.

“Maintain a healthy weight, stay hydrated, and don’t get dehydrated,” he said. “Don’t sit for unusually prolonged periods of time. You want to be up and moving around, because movement is what gets the circulation that veins in the legs need to stay active and not clot.”

It would be beneficial for residents who have a family history of stroke or heart attacks to get checked for genetic risk factors.