This morning I cut the grass. When I started the temperature was about 82F (about 28C). When I finished about 12:30 the temperature was about 100F (about 38C). The back yard, which is actually all that really counts, is about 5,000 sq. ft. (465 sq. meters).

I took three breaks and drank about a liter of water. In addition I had six small slices of salted watermelon.

I laid down and took an hour's nap. I awakened with a roaring headache and lethargy. It didn't occur to me what the problem was until around 4:30 -- and then I dissolved about a half-teaspoon of table salt into about 1/4 liter of water and drank it; I almost immediately began to feel better.

After dinner my wife went out and bought some "sports drink" (Gatorade). It's in the fridge and will be there for when it's needed.

Please, if it's hot where you are, and especially if the humidity is low as it is here, stay hydrated and watch for signs of electrolyte imbalance. If you work or play outdoors be especially careful. Drink plenty of water -- better to pee it away than to end up in the hospital.