Originally Posted by DrIsotope

As someone who has spent his entire life in the same inland desert, and is 100% heat-acclimated, I stand by what I said before: unless someone is paying you to pin on a number, there's no reason to ride in extreme heat. There's no reward.

Two weeks ago, I set out to do 166 miles, knowing full well that I would spent at least part of that in temperatures above 100º. And I did. I drank over 9 liters in 9 hours, spent 3 hours above 105º (peaking at 117º) and cut the day short at 140 miles.

I felt fine enough, I paced it well, I dressed appropriately... but it took about 4 days to properly recover. I gained no weight, so I sweat out at least 9kg of water, and it never dripped down my face once.

The only reason the extreme heat didn't win that day is because I absolutely know how to pace, and what to look for body-wise. But it was dumb. I shouldn't have done it at all.

Ride early or late. That's what I mostly do. I try. Sometimes, going against my best interests is just what I do.