Not sure if this is up your alley, but you might be better off searching for a model to do a sweaty custom video for you instead. I can't speak for every model, but I know lots of us put time and effort into our hair/make up/outfits and often plan to keep them maintained during our shows. Just something to consider!
I occasionally will do dance/work out shows where things can get sweaty. They haven't been very successful lately, so I haven't done any in a while. However, if you wanted to arrange a private work out show on MFC, I would be happy to discuss details with you privately! You can send me an MFC Mail here: MFC.im/Picnic