I had a long day beginning early morning with some fence repairs. Then I mowed some hay until noonish-no cab/no AC. Short lunch break and did some repairs then back to mowing again-- cab with shall we say, conservative AC the air blowing out was slightly cooler that outside temp. Then up to the north farm to work on some corral fence-direct sun w/o a hint of breeze. Son finally showed up around 4PM and wanted to get a full afternoon's work. By 7 PM, I wasn't feeling so good and nauseous. Son put me in his pickup and turned the AC on which set off the muscle cramps. I finally told him I was heading home and could barely keep the pickup on the road due to muscle cramps. Did my evening chores and came in for a quick shower. Feeling better now but still having cramps. Tried some of Son's recommended dehydration therapy stuff and haven't puked it up yet. It's not like I wasn't drinking water-probably swilled down almost a gallon since lunch. 