You know, that 62% effort, I wore a long sleeve thermal layer and no fan, so I'm sure that my water loss there was a problem now that you mention it. On the flip side, I rode at 74% for 2.5hs, but just wore the bib and did have a fan - heart rate was only 134 avg. Plus, I lost more lbs of water on that 2hr 62% effort. As much as I like seeing a lower number on the scale, I need to rethink things as that's not a great approach. Thanks for the info!!!