Notes
I didn't really want to go swimming but it turned into a really good swim! I used the first and last reps as warm up/ cooldown, and went relatively hard on the middle two. The third one at 7:42 was quick and I definitely put some muscle into it, but it wasn't nearly as labored as when I timed myself at a 7:35 for a 500. 4 x 500 @ 10 minutes (8:40; 8:11; 7:42; 8:30)