By the time Clyde Simms was forced to retire from the New England Revolution at age 31, his kidney function was down to about 20 percent.
The reason? Focal segmental glomerulosclerosis, also known as FSGS. He was diagnosed with the disease while he was in high school but still managed to have a nine-season career in the MLS — the last two years coming with the Revs.
Simms eventually had to go on dialysis, and after a first kidney transplant failed, he underwent a successful kidney transplant in December 2014. Simms dealt with severe complications along the way, but his lifetime of soccer training paid off in a huge and unexpected way.
"I was in the hospital for an allergic reaction, and unfortunately what I was having a reaction to, they were still pumping into my body so I was getting worse and worse and they just could not figure it out. No one knew," Simms told NBC Sports Boston. "My temperature got up almost to 108 [degrees] and everyone was rushing around the room, throwing ice on me.
"Once it came back down, the doctor came in to talk to me. He said, 'The only reason why you survived — or survived without brain damage — is because you were so fit.' It basically saved my life, and so my passion for fitness grew even more."
What did Simms do with that renewed passion for fitness? He decided to help other people get fit, by co-founding Rev'd Indoor Cycling.
After starting the company in 2004, Rev'd operates in three locations, with three more under construction.
And while Simms says cycling is easier on the body and joints than other exercises like running and cutting, it also provides other benefits, like building a community with other participants.
"There's nothing like going into something with a team, with all like-minded people. You seem them working as hard as you're working, putting in as much effort as you're putting in. I no longer miss that part of it. I obviously miss my old teammates and keep in touch with them, but the fact that I have a good team here helps me to not miss it so much."
For more about on Simms's story, check out the video above or click here. And for more on mental health in sports, check out more Headstrong content on NBCSportsBoston.com or on NBCSports.com.
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