Can anyone recommend a fairly accurate real time heart rate monitor please? It also needs to be water resistant. I don't mind if it's measured by a chest strap or any other method, but I do need to be able to see what's happening so a wrist watch type receiver is needed (or other I haven't come across yet). A phone app type isn't suitable for what I want it for.
I've looked at Fitbits etc but need something a bit more heavy duty for sports.