Mike Sheehy, the youngest in a family of four boys, has been running since Day One. And he never stopped. Sheehy ran track in high school and college and has gone on to complete more than 100 marathons and ultraruns. But when he suddenly couldn’t keep his usual pace, he ran to see a doctor. The diagnosis took his breath away — a heart irregularity. “My quality of life is running, being active, being outdoors and challenging myself,” said Sheehy, who works in Abbott’s Business Technology Services. To continue this lifestyle, Sheehy needed to get a pacemaker implanted. So he did: Abbott’s Assurity MRI device. Four months later, he raced the Boston Marathon. “I had run for so long on a weaker heart, now my heart was beating at full strength. I felt like I was unstoppable,” Sheehy said. This is a pretty common feeling after a pacemaker is implanted, according to Phillip B. Adamson, M.D., Chief Medical Officer for Abbott’s Heart Failure business and a cardiologist. “You walk in with a heart condition and you essentially walk out without the condition’s impact on your life,” Adamson said. How Pacemakers Work Pacemakers are medical devices that use electricity to restore the heart’s rhythm. When the heart beats in the normal 60-100 beats per minute (bpm) range, it can meet the body’s needs, pumping blood through the heart to the lungs where it gets oxygen, moving that oxygen-rich blood through the body and then returning it to the heart to restart the process. But if the heart beats too slowly — typically fewer than 50 bpm — the body won’t have the support to do what it needs to do. People will often experience symptoms such as not being able to climb stairs or walk without getting winded and sometimes even losing consciousness. In a millisecond, a pacemaker can sense if there’s a slow heartbeat and sends electrical signals to the heart to correct the rhythm. An important exception to this is endurance athletes, particularly long-distance runners, who sometimes have a resting heart rate as low as 35-40 bpm, Adamson said. “These athletes don’t usually need pacemakers,” Adamson said. “They have trained so much in long distance exertion that their nervous system ratcheted down the beats per minute their heart needs to beat to support their bodies, and they don’t have any symptoms of this low heart rate.” That’s where Sheehy’s case was different. He was experiencing symptoms, and this was a red flag for his doctors. “Even though I was a little sad and confused about what was going on with my heart, getting an Abbott pacemaker has enabled me to see first-hand how we help people continue doing what they love to do,” Sheehy said. Now, not only is Sheehy still running, but his new pace is very close to his old one. And he’s got some pacing tips to help push you to the top of your game too.