Double Olympic triathlon champion Alistair Brownlee has announced his retirement.

The 36-year-old Briton became the first triathlete to successfully defend his Olympic title when he won gold in Rio de Janeiro in 2016, four years after triumphing on home soil in London.

“It’s time to close this chapter… This marks my transition from professional triathlon, a moment approached with both dread and excitement in equal measure,” Brownlee, whose first significant title came in winning the 2006 Junior European Duathlon, wrote on social media .

“Why now? It feels right. I am happy and content, eager for what lies ahead. I find myself smiling because it happened, rather than crying because it’s over (to paraphrase Dr. Seuss).”

Brownlee was also individual World Triathlon champion twice, won the European title four times and competed alongside his brother Jonny, two years his junior, at elite level.

Jonny also won medals in London and Rio, and was famously helped across the line by his brother at the World Triathlon Series Final in Mexico in 2016 after nearly collapsing a few hundred metres from the finish.

Brownlee is now considering what his next steps are away from the sport.

“I look forward to embracing a slightly slower pace of life, yet not too slow,” the Yorkshireman added.

“There’s an exciting array of events, challenges, and adventures awaiting me — things I’ve always wanted to have a crack at but haven’t had the chance to pursue.

“For me, sport has always been a personal journey of exploration, and I’m excited to try some new challenges. Feel free to make suggestions below.

“First, I have many wonderful people to thank and some well-deserved relaxation to embrace.

“In the coming months, I’ll share more about my career and the incredible individuals who have been part of my journey, along with the new and exciting challenges and projects I’m eager to tackle.

“I am deeply grateful to each and every one of you for your contributions, no matter how small you may believe they are.

“Your support means the world to me. Thank you from the bottom of my heart.”

Brownlee announced his potential by finishing 12th at the Beijing Olympics in 2008 aged 20 and by the following year was the best triathlete in the world.

He maintained his dominance for most of the next decade but increasingly struggled with injuries and illness during the latter stage of his career and missed out on selection for the Tokyo Olympics.

Brownlee then switched his focus to long-distance events, with his final race coming at the T100 Triathlon World Championship Final in Dubai last Sunday, where he finished third.

“I was pretty confident all year that this was going to be my last year racing, but I wanted to get to the end of the year and really see how I felt without making a rash decision,” he said.

“It has got more difficult for me. I can’t do anywhere near the training that I used to be able to do. So I also found it hard at times being on the start-line, knowing that I’m not prepared to the level that I’d like to be.

“I’ve been planning for this day for a long time. I’ve always had a pathological fear of having nothing to do and I didn’t want to wake up the morning after my last race and I’ve nothing to do apart from go to the pub. That would be a disaster.

“So I’ve got all kinds of things and projects that I’m really looking forward to, excited to do and stay active, stay involved in sport.”

The brothers set up the Brownlee Foundation 10 years ago to help children get involved in sport, while Alistair is also a member of the International Olympic Committee Athletes’ Commission.