Tired is when

you swim 1.8km and then go for a 3 hour plus bouldering session.

It's been years since I last did rock climbing, the last time probably being in secondary school. I had a blast this time as I think I am slightly fitter this time round and could manage to have more strength to last longer throughout.

You don't really feel tired during the whole session as you're running quite a bit on adrenalin, but after the whole thing, I realized I was aching in places I didn't even realize existed.

Another thing that I learnt: Don't lean against a rock wall, it hurts.