The Biggest Loser host appeared on theTodayshow on Tuesday, where he talked about suffering a near-fatal heart attack in late February. The 51-year-old personal trainer was exercising at a gym in New York City, when he suddenly collapsed.
"I had what they call a 'widow-maker,'" he told Today co-host Savannah Guthrie. "It was a six percent survival rate, and the fact that there were doctors in the gym when I had the heart attack saved my life."
"I was in full cardiac arrest," he added. "My heart stopped. Not to be dramatic, but I was dead. I was on that ground dead."
Harper said he doesn't remember anything about the fateful day, when two doctors performed CPR on him and administered a defibrillator, which delivers a dose of electric current to the heart. He woke up in the hospital a few days later after going into a coma.
"It was super scary for me because I woke up and I was so confused," he shared. "I was like Dory from Finding Nemo because I had this short-term memory, so I was reliving the heart attack over and over again. I was like, 'Wait, why am I here? What happened to me?' And 10 minutes later I was asking the same thing, and getting super emotional."
Harper said that the "hugely shocking" incident did teach him an important lesson -- that it's important to know your health.
"I've learned a lot about myself," he acknowledged, adding that the experience was a huge wake-up call. "I've learned a lot about the fact that genetics played a part in this. It is so important to know your health."
"I'm a guy that lives a very healthy lifestyle, very regimented," he continued. "I work out all the time, but there were things going on inside of me that I needed to be more aware of. And I strongly encourage anybody that's listening right now to go to the doctor, get your cholesterol checked, see what's going on on the inside, so it doesn't happen to you -- what happened to me."
Watch the video below for more on Harper's scary heart attack.