Just past midnight, on the second lap of a 126-kilometre night run, Koen van Meeuwen felt great, and decided to end the goal he'd spent six and a half years chasing.

He'd stopped wanting to do it. He only wanted to have done it.

Koen has finished a quintuple ultra-triathlon, five Ironman distances back to back, without stopping, plus a triple, four doubles, and more than a hundred marathons and ultras. He learned to swim as an adult.

This conversation isn't about the distances. It's about the first time he had a panic attack during a race. About getting off the bike after 300 kilometres and deciding that stopping was the smarter choice. About rupturing his ankle ligaments two weeks before a race he'd trained a year for, and the 268 days it took to come back. And about what the people who do this are actually like, because they're not who you think.

Jacky Camos Wiewel is 55, teaches English at a primary school near Girona, and had barely exercised until she was 45. This summer she became one of roughly ten people ever to finish a 6 Split - three Ironman-distance triathlons on three consecutive days, then another three continuously, inside 61 hours. Mostly without a support crew.

We talked about the word "useless", the son who crews for her, and what she did on the Tuesday after.