Diego Sanchez has a lot of stories to tell, about fighting and life.

His latest? That medical marijuana caused him to have serious heart problems that, for a time, left him concerned about the future of his fight career and even his life.

In an extended interview with broadcaster Ariel Helwani on Monday on The MMA Hour program, Sanchez—who faces Al Iaquinta this Saturday at UFC Fight Night 108—described a recent sparring session that ended when he experienced serious discomfort in his chest.

"I hit the ground, and I felt something inside my heart," he recalled. "It wasn't, like, a muscular injury. It was something internal. ... I just laid down and said, 'I'm done for the week.'"

Minutes later in the interview, he said, "The moment I laid down at the back of [that gym], I instantly knew it was because of that medical marijuana."

Sanchez, who said he obtained a medical marijuana license after a fight in November and had been smoking the drug experimentally for the past several months, did not initially seek medical treatment for the discomfort, but hypothesized that his heart was palpitating or not receiving enough oxygen. 

"Whatever happened, it was serious," Sanchez said. "I could feel something going on, and I was very, very terrified that if I got my heart rate back up that I could, like, die or something."

Sanchez said he still felt "uncomfortable" the following morning and for days after. Instead of going to a hospital or doctor, however, he chose to fast and pray for several days, taking time off from training. He told many at the time that he had the flu, but internally he remembers thinking, "What if my career's about to be over?"

After that, Sanchez did visit the hospital, at which point he said the doctors told him he had "a perfectly fine, healthy heart," and that what he was feeling was "a muscular injury."

"I received a miracle that day," Sanchez said. 

But Sanchez didn't believe it was a muscular injury. 

"My lungs were being affected," he said. "And I still had the mentality to train like a warrior, so when [the heart issue] happened to me, that day at the gym, I was still experimenting with medical marijuana. ... I did it, and I loved it, and I got my medicinal medicine. ... I'm not judging. I'm saying that medical marijuana's not for everybody, and it's not for me."

A 2016 study from St. Luke's University Health Network in Pennsylvania found that marijuana use can weaken heart muscles, but only temporarily and right after smoking. The condition is not serious, but symptoms can mimic a heart attack and may include chest pain, shortness of breath and dizziness.