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NASCAR driver Brian Vickers will compete in the Daytona 500 this weekend, marking his return to racing after a life-threatening health condition forced him to temporarily sideline his career.

In May 2010, Vickers was on a bike ride with a friend while visiting the Washington, D.C. area when he noticed something was off.

“[My friend] is in good shape, but not like a professional athlete is, so I should always beat him,” Vickers, a 2009 NASCAR Sprint Cup Chase Contender, told FoxNews.com. “And he was crushing me, for the first time ever.”

Though he wasn’t experiencing any pain at the time, Vickers noticed he was having trouble catching his breath – but as a healthy 26-year-old, didn’t think much of it. Yet, the next day, his conditioned worsened, and Vickers began experiencing chest pains and shortness of breath. The discomfort, which came and went, grew progressively worse throughout the day.

“Eventually, every breath was the most painful experience I ever had in my life,” Vickers said. “It was horrendously painful in my chest and that’s when I had had enough and went straight to the hospital.”

Though doctors initially suspected pneumonia, they ordered a CT scan – during which Vickers could barely lie down on the table without losing his ability to breathe. Eventually, doctors spotted the problem: there were several blood clots in Vickers’ veins, including one that had travelled to his lungs.

“Even then, I didn’t quite understand the seriousness of the situation and told the doctor, ‘We’ve got to get this fixed quick— I have practice Friday,’ and this was Wednesday,” Vickers said. “And he was like, ‘Son, I don’t think you understand the situation.’”

‘It almost cost me my life’
Vickers had developed a life-threatening condition called deep vein thrombosis (DVT), in which blood clots form deep within the body’s veins – typically, in the legs. In Vickers’ case, one of the clots had broken off and travelled into his lungs, blocking blood flow and causing a pulmonary embolism – which can be fatal if untreated.

“Because I waited and ignored the symptoms, it almost cost me my life,” Vickers said.

Vickers was initially placed on Coumadin, a type of blood thinner, to treat his condition. While on the drug, he had to return to the hospital for constant monitoring and stick to a strict diet, avoiding certain foods and alcohol.

Though his health improved with treatment, Vickers was uncertain whether he’d ever be able to return to racing.

“Basically, no matter what blood thinner you’re on…it thins your blood and there’s always the risk of bleeding,” Vickers said. “Ultimately, it came down to whether or not I’d be on blood thinners temporarily or permanently. That was going to determine whether or not I was going to race.”

Later in 2010, after six months of treatment, Vickers was cleared to stop taking blood thinners and return to racing.

‘Lightning struck again’
But, unfortunately, that wasn’t the end of Vickers’ struggle with DVT.

In October 2013, while at Bristol Motor Speedway in Bristol, Tenn., Vickers sprained his foot – an injury that forced him to wear a boot for about a month until the injury healed.

“Lightning struck again…when I took the boot off I had this knot, almost like a deep bruise in my right calf and a little bit of swelling. Not a lot…but enough I could tell something was not right,” Vickers said. “This time, knowing those signs and symptoms, I immediately called my doctor and went in for an ultrasound.”

Vickers’ had developed another blood clot, in his right leg, and was again forced to go on blood thinners and put his racing career on hold.

This time, Vickers’ was placed on the blood thinner Xarelto, which required less monitoring and didn’t involve dietary restrictions. And because his clot was less severe, he was on blood thinners for only three months.

Finally, in January 2014, Vickers was cleared to race again.

The road to recovery
Doctors aren’t sure why Vickers’, now 30, developed DVT. Though spending long periods of time sitting – such as in a car, or during a long flight – can be a risk factor for DVT, experts don’t believe his racing career was a factor.

“You are in constant motion [in a race car]. I’m putting on the brakes, depending on the track, anywhere from 500 to 1,000 pounds of pressure on every turn, every lap, which takes a tremendous amount of force and blood flow…,” Vickers said. “It’s a very different environment than sitting on the plane for six hours, though you are seated. The determination is, because of the activity in the car, it’s not the same risk.”

As a result of his experiences with DVT, Vickers, who now resides in Miami, Fla., became a paid spokesperson for Janssen Pharmaceuticals, Inc., the manufacturers of Xarelto, in an effort to raise awareness about the signs, symptoms and risks of DVT though the website TreatMyClot.com.

“If you have pain in your chest, or your legs are swelling, something is wrong; it doesn’t matter how young or healthy you are, something is clearly wrong and you should seek advice and counsel from a doctor and get it checked out,” Vickers said.

Luckily, Vickers has had to change very little about his training regimen – and is looking forward to continuing to pursue his racing dreams, starting at the Daytona 500.

“It’s my goal is to win a championship…I love being in the car, going fast and I love what I do,” Vickers said. “As far as goals, I’ve been fortunate to accomplish all goals I’ve set in racing other than to win the championship. I’ve won races at all levels, but I haven’t gotten that final trophy.”

For more information, visit TreatMyClot.com.