You can be 100% fully hydrated and topped off food wise and still get overheated. You can sweat at max ability and have the hydration to support that. That sweat can evaporate at max rate possible for the conditions. That is the best you can get. If that is not enough heat shed to keep you cool, you will overheat. Proper hydration is not a free ticket to any amount of extreme heat or exercise, it only sets you up for the best possible chance. What someone said above, once you have the uncomfortable stomach and queasy feeling you are in the stages of heat stress meaning you are actively overheating. Finding the right food that you can tolerate in that state is not the answer. Maybe you were a little dehydrated and not sweating at max ability and some fluids can turn it around. Maybe you were already "topped off" and it is what it is. It's time to cool your body down somehow some other way. Go stick your head under a hose, dump a water bottle on your head, sit in the shade, ride around really slow in the shade and get a slight breeze. You can try to ride it out but I've found that feeling lasts for hours after the ride, drinking a lot of water two hours after you are done still feels uncomfortable. One of the worst helpless feelings is riding hard in the sun for a while and coming to a stop on the 150F pavement with no breeze next to a hot car reflecting even more heat while you are waiting for that green light. I guess another one is finding some shade on a trail but there is no breeze and tons of mosquitoes and biting flies.
Last edited by u235; 07-18-19 at 03:14 PM.