HRM WITHOUT a watch

Ok I realise I'm probably clutching at straws here but is there a HRM without a watch? I did a quick google but I couldn't find anything. Reason being I do ju jitsu and my chest is about the only part that doesn't get pummelled we do takedowns frequently, leg reaps (which means anywhere from my thigh to ankle getting hit) wrist locks which mean I cant wear it on my wrist and blocking punches which means a whack to the upper arm.

So.... I want a HRM which can track my calories doing ju jitsu, but I want one without a watch, or at least which transmits about 30-40ft to allow me to leave it next to my water. I also dont have pockets on my gi and since I spend a lot of time on the floor its not practical to put it anywhere on clothing because it would get smashed.

Anyway :) thanks in advance x