When we experience excessive stress-whether from internal worry or external circumstance-a bodily reaction is triggered, called the "fight or flight" response. Originally discovered by the great Harvard physiologist Walter Cannon, this response is hard-wired into our brains and represents a genetic wisdom designed to protect us from bodily harm. When we face very real dangers to our physical survival, the fight or flight response is invaluable. Today, however, most of the sabertooth tigers (ancient real danger) we encounter are not a threat to our physical survival. Today's sabertooth tigers consist of rush hour traffic, missing a deadline, bouncing a check or having an argument with our boss or spouse. Nonetheless, these modern day sabertooth tigers trigger the activation of our fight or flight system as if our physical survival was threatened. On a daily basis, toxic stress hormones flow into our bodies for events that pose no real threat to our physical survival.