Olympic medalist David Plummer retired from swimming this week by penning a heartfelt farewell letter to the sport that has captivated him since he was 5 years old.

Plummer won two medals at the Rio de Janeiro Games this past summer: bronze in the 100-meter backstroke and gold in the 4x100 medley relay. At age 30, he became the oldest first-time U.S. Olympic swimmer since 1904. Plummer was also the first Gophers swimmer to make the U.S. Olympic team in 52 years.

"I haven't been in the water since Rio, so this has been true for a while, but now I am saying it out loud and I am admitting it to myself. I am retiring. I am done swimming," Plummer wrote in the letter published by SwimSwam. "This was a hard decision to make. I have defined myself as a swimmer since I was five years old, but it comes down to this: I don't want it any more. The majority of my life I have wanted to swim fast more than I wanted to breathe. I don't want it that way anymore."

The Oklahoma native finally earned a spot on the U.S. swim team in his fourth Olympic trials appearance. In 2012, he placed third in the 100-meter backstroke. The top two swimmers advance to the Olympics.

"I have been told by many people since the Olympics that they were inspired by my perseverance," Plummer wrote. "I always just thought I was a slow learner. Honestly, I just couldn't find a way to step away when I still had more to accomplish, more to prove to myself. I am humbled to walk away as a member of the U.S. Olympic fraternity. I got to be a member of the U.S. Olympic Swim Team and I'm proud of the way we competed."

Plummer also thanked his friends, family, teammates and fans for the support he's received throughout his career, with a special thanks for his wife and mom.