Republican Sen. Thom Tillis of North Carolina says he's "fine" after collapsing during a Washington, D.C., race and being taken away by ambulance. Three men rushed to aid the senator after he collapsed.

Tillis posted a video on Twitter from his hospital bed Wednesday morning saying he was OK.

In the video, Tillis says: "Hey everybody, I'm fine. Just running about 2 and a half miles in and got overheated, no CPR, no special measures, just checking me out. See you back on the Hill."

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Tillis, 56, was seen on the ground at about 15-20 minutes into the race, which started at 8 a.m. The three-mile race was being held in Anacostia Park in the southeast part of the city.

Debra Alfarone was running the ACLI Capital Challenge along with the WUSA9 team and 650 other runners and happened to be in the right place to get the story.

Debra: I’m running down Anacostia Park in SE when I see a man down. I stop and see three men working to save another man’s life.

TJ Cooney, who works for AARP was the first to see the runner in trouble.

TJ: I just saw from his face that he was unconscious. He was having trouble breathing and one of the other runners started doing CPR.

The second runner told Debra his name is Matt Flood and he works for U.S. Capitol Police. U.S. Capitol Police declined Debra’s request for an interview. Debra found the third man later at his job at the Department of Education.

Dr. Jesse Maggitt: I said 'hey, lets get his airway going, let’s make sure he has a clear airway.'

TJ Cooney: I was checking his pulse and we’re making sure he had an open airway and then when he started seizing, we put him on his side…..He did stop breathing at one point.

Dr. Jesse Maggitt: Number one, you open his mouth, look inside to make sure there’s no obstructions, and to be sure there was nothing in there, we turned him on his side.

At first the men said they didn’t realize who they were helping. It turned out it was Senator Thom Tillis of North Carolina.

The Senator tweeted a picture of he and his team before the race and he was smiling.

Two miles into the three-mile race, he started experiencing problems.

Debra: Did you even know who you were helping today?

Dr. Jesse Maggitt: No not at all, I didn’t know who the person was. Debra: How did you know how to help?

TJ Cooney: I was a lifeguard when I was in college and it’s just part of the training.

Dr. Jesse Maggitt: My instinct comes from the fact that I’m an ex Navy corpsman, served in the military for over 20 years.

Debra: Some say you’re a hero.

Dr. Jesse Maggitt: I don’t see it like that, I just see it as a person trying to do what’s right, even when no one’s looking.

A second person needed medical attention at the race today. Fidelco Guide Dog is the beneficiary of the money the race raises. It was their Director of Guide Dog Training Operations, Tommy Mourad. The company says he is resting and a positive outcome is expected.