9781422287729

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STRESS AND TENS I ON

In a situation like this, you have to decide: are you going to fight—or run away?

“fight-or-flight response.” This response is the body’s natural reac- tion to a challenge. When this response was evolving , thousands and thousands of years ago, danger was something that had to be either fought or run away from. If your long-ago ancestor was facing an angry bear, for example, he had to either attack it and kill it—or run away from it as fast as he could. As a result, his brain sent out messages to the rest of his body, getting him ready to either fight or run away. His heart beat harder, and he breathed faster, send- ing more oxygen to his muscles. His digestion slowed down, while his blood pressure increased, so that more blood could go to the muscles in his arms and legs. His pupils dilated so he could see better. His muscles tensed, getting him ready to move . In today’s world, danger is often not quite as simple—but our bodies don’t know that. They still get ready for fight or flight, the