Weight

 83.75kg this morning.  Lowest recording yet.  I think most of that was sweat though as I came back from the gym dripping!

Lightest i've ever been

 Or to be strictly true since I was 18.  That's 85.95kg!

At this rate i'll make the next olympics!

 As predicted, I beat my 100m swim time.  1:52, beat it by another 3 seconds!  Or 3% better.   What I didn't predict was also beating my 500m swim time 11:01.  That's by 7 seconds!  Or a 1% improvement!