One player suggested this at HOTS Beta US forums
Because I can't post here due to EU account only, I'll say here a small instruction how to toggle HP bars in game.
1) Rebind HP-bars hotkey to double-hotkey. I mean from ALT (default hp-bar hotkey) to SHIFT+B or ALT+`. Lets look at SHIFT+B combination
2) In game press SHIFT
3) While holding SHIFT press B
4) While holding B push out SHIFT
5) Push out B
Thats it! At same way you can block camera rotation, if you rebind it to double-hotkey combination.