From what I can tell, your shield is separate from your character and they don't share each other's stats. It has it's own health bar which regenerates slowly, and all of the damage you take while the shield is active is directed to it instead using its own defense. But while your shield isn't raised, it's effectively doing nothing for your character (barring any extra abilities, like the attack speed increase of the Bristling Buckler)

http://wiki.spiralknights.com/Shield

"Shields have defense and health, just like a player. When a shield blocks a hit, any damage that gets past its defense degrades its health. Once a shield reaches zero health, it breaks, leaving the player open to damage. When not in use, the health of the shield will regenerate. Note that the damage resistances of a shield only apply when the shield is in active use."

Does that apply to the status resists as well? It would seem strange to have the shield resist a status when you shouldn't get that status anyway if the shield is blocking the attack.

Shield status resistances mean that shields take significantly reduced damage from attacks that indlict that status effect.

You can test this by bringing an Emberbreak Shield into the Advanced Training Hall and seeing how long it holds up against the fire grate versus the ice or shock grate.