That's not what the core books say... it says your resistance is increased temporarily. Otherwise, it would never be worthwhile spending courage points on that... far more efficient to spend them increasing your dodge roll.
But in situations where you are being hit a lot for a small amount of damage each time, it makes sense AND models the shows and cinema well (capturing the feel of Kirk roughing it up for several minutes on end) to resolve it as the ICON core book describes.