BILLINGS Billings resident Don Gleason was diagnosed with heart failure 15 years ago, but he hasn't let it slow him down. While his journey to acceptance has been anything but easy, he's managed to adapt to his limitations, while enjoying some of the things he used to. Gleason who has always been active in the outdoors first received the earth-shattering diagnosis when he was 49 years old before a routine shoulder surgery. Gleason shared with the medical team that he had experienced weird moments with his heart and felt more limited when working out. Well, the first signs were just that I was having some heart palpitations, Gleason said. I noticed that I had really slowed down. I always ran and I would run long distances, but I was definitely slowing down." So, the medical team ran some tests, and that's when Gleason received the diagnosis.  They had discovered that my mitral valve had gone bad and that I needed surgery to repair the mitral valve, Gleason said. "Basically, my heart wasn't working like it was supposed to." Over the next 15 years, Gleason underwent more than 10 surgeries to manage his heart condition, which altered his life. Its a grieving thing, you know, a lot of it," Gleason said. "Just grieving the things you cant do that change your life."Before the diagnosis, Gleason stayed busy running, hiking, hunting and fishing. His heart currently pumps with only about 15 percent output compared to the usual 55 to 70 percent which is why so much about Gleason's life has changed. I thought I was going to get everything back at some point, but that didnt hold true, Gleason said. Ive learned to adapt. Its at the point now that I understand things are going to be different and thats just the way it is." It was a process getting to that point. Gleason said he owes a lot to his wife, Linda Gleason, who has been supportive at every step. The only challenge for me, its really hard to watch someone else suffer, Linda said. "He's so active and just a workout enthusiast, so finding those balances of what were in those boundaries. That was a challenge." Billings Clinic Cardiologist Dr. Joseph Muhlestein said that what Gleason manages to do is still very impressive. "I mean 15 percent is extremely low," Muhlestein said. "A lot of people that are that low, theyre having a hard time walking across the parking lot, theyre staying in a chair, they really are just not able to be engaged with life." Muhlestein said that's a testament to Gleason's discipline and overall health. "It helps when someone is in that good of condition before something like this," Muhlestein said. "You're going to lose things but if you start off healthier that makes a big difference." And while Gleason has adapted to his new reality, it doesn't mean the losses aren't overwhelming. I grieve," Gleason said, as tears welled in his eyes. "From what I used to be able to do. Seeing the high country. Thats a tough thing."Still, nothing compares to the quality time he's been able to spend with his family, which is something his wife gladly reminds him. Our kids are in a different age, Linda said to Don. They just need your brain and your heart. They dont need your legs.It's been a lifetime full of challenges and changes which Gleason has continuously met head-on. "I just keep doing the best I can, so I'm doing great now," Gleason said. "I love life and I'm doing great right now."