Went out yesterday around 1100 after procrastinating doing something or other. 95F with a Heat Index of 108F. In 21 mi. I drank 1.5 qt of water, 1 qt of electrolyte, 1 large cup of coffee and had a cream cheese filled croissant (beats gels any day of the week).

Came home with a 2 lbs of water deficit (so said the scales) and a slight headache. Drank another quart in the next hour and eventually the headache went away.

I am not going to do this again...