My missionary friends in the Philippines told me to use lime juice to help acclimate to the heat. Not sure exactly how it works, but DH is a definite convert, he's been guzzling lime-aid (lime juice, water & liquid stevia) for over a month now and doesn't sweat & overheat nearly as much as before. He's home all day and doesn't like to use the ac unless its killer heat. I'm in an air conditioned office all day, so I haven't noticed much of a difference.