Well, earlier that day I was splitting (with a maul) some huge Walnut logs and I had also been doing some work in the yard. I may have arrived a bit "dry" and I've had heatstroke before during a live-burn fire training drill that was held in August, and I know this makes me more susecptible to it. All I can say is that I need more water than some other folks. Glad I always have some.