Phil Mickelson has made it to almost 55 years old (his birthday is in a week) and is still a professional golfer. He's on LIV Golf, but he still competes regularly, so his health is not an issue even at his increasing age. That was once something that didn't seem so likely.
When Mickelson was 40, he suffered from psoriatic arthritis, a painful condition that not only threatened his golf career but his overall well-being as well. It's a condition that causes his immune system to attack his joints and tendons, leaving victims in serious pain.
In 2010, Mickelson said of his illness via ESPN:
"I'm surprised at how quickly it's gone away and how quickly it's been able to be managed and controlled," he said. "I feel 100 percent, like I say. But when I'm laying there on the couch and I can't move, you know, yeah, I had some concerns. But I feel a lot better now."
He admitted that it left him feeling concerned:
"I certainly had the gamut of thoughts. ... I would just lay down and I couldn't roll over. I was concerned about being able to swing a club and so forth."
Ultimately, he got through that difficult period and went on to have another excellent run of golf in the years after this.
What Phil Mickelson did to mitigate the psoriatic arthritis issue in 2010
Phil Mickelson was taking shots at the time to help get the disease under control, which helped. The former Major champion didn't necessarily cure himself, and he admitted that it could come back in the future, but he found a way to manage it.

He added via ESPN:
"I feel great now and things have been much, much better. I'll probably take this drug for about a year and feel 100 percent. I'll stop it and see if it goes into remission and it may never come back. It may be gone forever... If it does come back, I'll start the treatment again and should be able to live a normal life without having any adverse effects. So I'm not very concerned about it."
Since then, Mickelson added three Majors to his career tally with wins at the 2013 PGA Championship, 2013 Open Championship, and 2021 PGA Championship. He also finished T2 at the 2023 Masters.
Mickelson also said at the time that he waited to reveal his condition to avoid any excuses:
"Now that I feel confident it's not going to affect not only the rest of my career or the rest of my life, but even in the short term it shouldn't have an effect, I feel a lot better about it and I'm a lot more at ease to discuss it."
Since then, Phil Mickelson has largely not struggled with his health at all.