According to my watch, I broke my swim record on NYE (a relatively modest 50*50m at the NSC, I usually do 50-60*25m daily, if I'm working from home, in the local pool). I'm sure I've done that many before, but I used more calories apparently. I mostly pass my boredom threshold around 50 lengths, but it was one of the days when the pool wasn't busy and the other person in the lane was matching my speed and everything seemed to come together so that I wasn't swimming like a bag of spanners. Fifty metres is also, in some ways, easier because you're not faffing around turning all the time, so I can zone out and contemplate important things like the pigeon that lives there, is it the same pigeon that's always there, does it just visit, does it have membership, etc? The staff there are so lethargically uninterested in anything I don't give them good odds of catching it unless it dies in front of them.