What do people do to keep the HR chest straps from sliding down when sweaty? I find that the straps usually stay in position during training runs. However the strap often slides down when running hard (in a race or workout) due to a combination of sweat and the v-shape of most non-fat people's chest. It doesn't seem to matter how tight the strap is. In a couple of races where I've tried using a HR strap, where I don't have time to fiddle with it, it ends up around my waist. Some straps are better than others, but the 3 or 4 straps that I have used have all had the problem to some extent.
It seems like HR chest straps could use shoulder straps like bras. Or maybe a layer of klister or kick wax from the ski tool box on the inside of the strap might work?