What is the most physically demanding thing you have ever done voluntarily and would you do it again?

[KnotKnull]

Not something you had to do. Something you chose. Could be a race, a climb, a long distance anything, a physical challenge of any kind. What was the hardest physical thing you have voluntarily put yourself through and looking back at the other side of it, was it worth the suffering?

Specifically interested in whether the experience changed anything about how you think about physical limits

[Mia_59]

A 100 mile ultramarathon in the Scottish Highlands in November. 36 hours. I hallucinated mildly around the 80 mile mark. It changed my understanding of what my body can do at the absolute margins of what I thought was possible. Yes I would do it again

[ShadowPilot]

Three-day wild camping in Norway with a 25kg pack and no trails. The weight was the problem not the distance. On day two I genuinely questioned every choice that led me to that hillside. On day three I understood why people keep going back

[TheLegendJohn32]

Open water swimming across a lake in 12 degree water in October without a wetsuit. Not far, 2km. But the cold changed my nervous system in real time in a way I had never experienced. Took three hours to feel warm again. I would not do it again but I am glad I did it once

[Leo]

A 24-hour charity cycle in the wet of February with no sleep allowed. The 3am to 6am section is a specific kind of suffering that is very different from physical fatigue. The mind has to do different things when the body is running on empty in the dark

[Dave_37]

Fasting for 5 days on water only as a deliberate experiment. Not physically dramatic in the exercise sense but the mental relationship with hunger and control changed in ways that have been permanent. Day three is when the hunger stops and something else takes over

[Fox]

Single day Munro bagging in winter conditions. 14 hours on the mountain, ice on the descents, hands too cold to work properly by the end. The part I remember is not the summit. It is the last hour when I was genuinely uncertain whether I had made a mistake about the conditions