Man riding racing bike with green orchard of trees in the background

Heart of a champion: How John Hannon went from open heart surgery to an Ironman triathlon


Having a heart condition can make it difficult to participate in athletics, but as John Hannon knows, it doesn’t make it impossible.

During the past year, Hannon completed three marathons and an Ironman triathlon despite undergoing open-heart surgery just five years prior.

Two open-heart surgeries

Hannon had his first heart surgery in 1993. It was a Ross procedure, a heart valve replacement to treat severe aortic valve disease. The diseased aortic valve was replaced with Hannon’s own pulmonary valve, followed by replacement of the pulmonary valve with a valve from a donated human heart.

Despite being just 27 years old, Hannon suffered from aortic stenosis. This occurs when the aortic valve narrows and blood cannot flow normally. The narrowing keeps the valve from opening fully, reducing blood flow to the body and making the heart work harder.

Man wearing medal around neck standing in the street next to sign that says California International Marathon
The California International Marathon in Sacramento was John Hannon’s first marathon.

“Following the procedure, I knew it wouldn’t be my last surgical heart procedure,” Hannon explained. “Due to the unknown length of survival of the new valves, I was eventually going to have them replaced.”

Hannon’s aortic and pulmonary valves held strong for 25 years. Then, he started not feeling right again. Now a Sacramento resident, Hannon made a late-night emergency room visit to UC Davis Health where doctors discovered he was experiencing atrial fibrillation (AFib), an irregular and often very rapid heart rhythm. Days later Hannon underwent a catheter ablation to shock his heart in hopes that it would take him out of AFib.

“Luckily the ablation was a success,” Hannon said. “But they also concluded that I needed a second heart surgery to replace my aortic and pulmonary valves.”

A few months later, Hannon again underwent open-heart surgery, this time at UC Davis Medical Center. During the procedure, he had the choice of either receiving two metallic artificial valves or two cow tissue valves.

“There were positives and negatives with both options,” said Hannon. “With metallic artificial valves, I would need to use blood thinners for the rest of my life. With the cow tissue valves, I would need them to be replaced one day again. Ultimately, I decided to receive the cow tissue valves because I didn’t want to be on blood thinners forever.”

John Hannon
I truly feel blessed to have gotten to this point. Throughout this whole experience, I have not had any limitations on what I can do. My cardiology team has supported me and pushed me to believe in myself.” John Hannon

Road to recovery

Hannon’s surgery was a success, but he still faced a long road to recovery.

“I still remember trying to go jogging six weeks after the procedure and I could not even make it one block,” said Hannon.

Determined to get back to his normal routine of being active, Hannon spent the next year walking daily and eating a plant-based diet.

“It took 13 months until I could run a block without stopping,” Hannon recalled. “But I didn’t want to stop there. So, I just kept working to do a little more each day.”

Slowly, Hannon was able to start hiking, running, swimming and biking. Eventually he decided to take a month off work and rode his bike from Roseville, Calif., to Orcas Island, Wash., covering 1,980 miles going up and down mountains on his route.

“It was something I always wanted to do, and I finally felt good enough to do it,” said Hannon.

Man wearing medal around his neck standing in front of sign saying Iron Man Competition
In the past year, John Hannon completed three half-Ironman triathlons (70.3 miles), two swim/run races and two Olympic distance triathlons.

When he returned from his trip, Hannon started training for a marathon. After completing one, he got involved with total body fitness training to prepare for a triathlon.

On Oct. 22, 2023, Hannon completed his first Ironman triathlon, which consisted of a 2.4-mile swim, 112-mile bike ride and 26.2-mile run totaling of 140.6 miles.

“I truly feel blessed to have gotten to this point,” said Hannon. “Throughout this whole experience, I have not had any limitations on what I can do. My cardiology team has supported me and pushed me to believe in myself.”

Hannon still receives care for his heart at UC Davis Health, where he regularly sees Jason Rogers, clinical professor of cardiovascular medicine.

“John is a remarkable individual. His dedication to his own heart health and fitness has allowed him to achieve amazing physical feats that even those without a heart condition could never accomplish,” said Rogers. “He inspires me, and I hope that he will inspire other heart patients as well.”