A study published in Biological Psychiatry looked at the effect of facial expressions of emotions, such as fear and indignation, on our stress response. They found that displaying anger may cause your brain to release less of the stress hormone cortisol.
The study focused on short-term anger and frustration, such as getting cut off in traffic, not long-term anger. The researchers believe that responding to this kind of anger gives the person a feeling of control over those little things that get to you by counteracting feelings of helplessness and frustration.
So, an occasional #XY!!XZ, might actually be good for women, too.
(Reported Prevention December 2010)