Thank you so much for this information. I especially apperciate that you have given reasons for everything you are saying. That makes it easier for me to remember!

My (very excitable) border collie had heatstroke and collapsed last summer following a walk with my neighbours two boisterous labs.
I phoned the vet who
instructed me to get him into a quiet dark place and place a damp towel on him. I now know I shouldn't have covered him with a damp towel. I did replace it with another damp towel frequently, though. He did recover, though it was very frightening.
At an agility show a few yesrs ago a dog collapsed and started fitting due to heatstroke. Fortunatly he recovered and there was no longterm damage.