A friend of mine is building himself a house and spends the weekend slaving away at it. Since he works 5 days a week it only allows him the weekends to get stuff done on his house. Since he only gets a day or 2 to work on it it usually causes him to over doing it but he doesn't mind it because this is the type of thing he enjoys.
Last weekend it was around 102 degrees and he told me the he got a little dehydrated and almost past out. This also resulted in him getting sever cramps later that evening. He said that the cramps were so bad that his hands were locking up and wasn't able to hold his fork to eat his dinner and when he went to lay down he couldn't extend his legs because the cramping was so painful.
Luckily his wife had some Magnesoothe and rubbed some on his hands and legs and within the hour the cramps were completely gone.
So, if you are going to beat the heat, make sure you drink plenty of water and use Magnesoothe to replenish your electrolytes.