Stress is more likely to be harmful if you feel helpless to deal with the problem or situation that causes the stress.

VOA: special.2009.03.24

The expression "to bulldoze" also means to make someone helpless, usually by using power or threatening violence.

VOA: special.2009.02.15

Otherwise a child could feel hopeless and helpless to do anything about it.

VOA: special.2010.05.06

I watched her for hours, helpless and alone with my breaking heart.

VOA: special.2009.07.25

But she was helpless in the viselike grip of the powerful man."

VOA: special.2009.08.24

It meant to make someone helpless, to trick them.

VOA: special.2009.02.15