But again, that is NOT confirmed. To me it sounds like you will have two "parallel" life bars, that will both be damaged at the same time. Not that one will "shield" the other.
It's not confirmed, I agree, so I offer nothing but my thoughts (after being asked). However, the example posted does suggest that the stamina acts a shield:
Here's an example. Bob the Fighter has 32 Stamina and 30 Health. He gets hit by a number of attacks that subtract 25 Stamina and 5 health (leaving him with 8 Stamina and 25 Health). He is a fighter, so he chooses to use one of his abilities to regenerate Stamina. He does this and quickly bounces from 8 Stamina to 15. Unfortunately, he gets smacked again for 20 Stamina and 4 Health. He is knocked out (effectively 0 Stamina) and at 21 Health. The guys who knocked him out move to other targets.
Francine the priest casts restore stamina on Bob when combat is over. He recovers to full Stamina quickly, but is still at 21 Health. Depending on how the next few fights go, they will either have to retreat to rest or find a safe resting spot up ahead."
Furthermore, from the KS page:
"
The majority of damage a character takes is subtracted from his or her Stamina. Stamina represents how much general abuse a character can take before falling unconscious.
Characters lose it quickly and regain it relatively rapidly, even without assistance."
aka a shield.