To everyone who says “you need to swim more/more often/join a masters/get a coach” you’re dumb as fuck. Literally all sports science is published online in peer reviewed literature. Don’t ask Reddit - ask pubmed. If you think the best people on the planet at what you want to do did so without medical science then you’re very much mistaken.

You need data and then you need to act on that data. Don’t blindly swim for 1.5 hours every week or whatever it is you do. Actually do the research to figure out how to get fitter because no matter where you are in your training - if you plateau and you’re not setting world records or at a pro level then you’re just being lazy - not in terms of working out but in terms of the knowledge required to actually push yourself so you train in the right direction.