Adapted from Is it Me or My Hormones?

In recent years, the word “stress” has taken on such negative connotations, but from the body’s point of view, it only means any type of demand or challenge that requires the body to expend extra energy. Getting up from your seat and walking across the room is a minor stressor, for example, because it requires more effort than remaining seated. Dinner with a sexy new romantic partner—thrilling as that may be—demands more energy than eating a bag of potato chips while sprawling on the couch. Mobilizing energy and expending it on a chosen task—rising to the occasion, in other words—is an essential part of what makes life interesting and rewarding.

But the stress response was never meant to be a permanent condition. The human body is designed to respond readily to challenges—and then to release and relax. We even have two complementary aspects of our autonomic nervous system to help us maintain that balance. The autonomic nervous system is the aspect of our peripheral nervous system that controls the activities of our organs, glands, and various involuntary muscles, such as the cardiac and smooth muscles.

  • The sympathetic nervous system mobilizes energy, preparing us to meet challenges of all types. Through a number of glands and organs, including the adrenals, it causes our heart to beat faster, our blood to pump more vigorously, our blood pressure to rise, our breath to come faster and deeper, and a number of other effects designed to help us face any demanding situation.
  • The parasympathetic nervous system stores energy, allowing the body to rest up and prepare for the next challenge. It causes our heart rate, blood pressure, and breathing to enter into a more relaxed state, and it also supports digestion and immune function so that our bodies will be in top condition next time life throws us a demand.