It seemed like the Dolphins were much less affected, at least to me. Maybe it was the shade on their side allowing them to cool off a bit.
Heat tolerance is an individual thing. I have no idea how Allen lasted the whole game without having issues. He was obviously gassed by the end when he one hopped the ball to Mackenzie in the end zone on 4th down.
I really worried about the big men who weight 300+ pounds and have all that gear on and have to maul (or be mauled by) another 300+ pound man every play.