We often find it challenging to maintain or re-start our physical activity programs after an event or circumstance interrupts the flow.  I am currently designing activities around a broken wrist and the admonition, "don't sweat in the cast!" Next month, I will be challenged to rebuild strength and fitness after falling out of the exercise habit.  Where do we find the inspiration to overcome the draw of a sedentary lifestyle?  

Several years ago, I found a book by Dr. John Ratey, entitled ­Spark.  Ratey makes a powerful case for the mental and emotional benefits of physical activity.  Research shows that health is not just about the heart, blood sugar, and body mass index.  It is about the mind-body connection.  In sharing a few insights from Spark here, I am barely scratching the surface.  I encourage you to read it for yourself.

 The featured topic is, again, stress.  Stress is a complex response to a variety of stimuli. It can include fear, anger, paralysis, or hyperactivity.  Stress responses are designed by nature to deal with an immediate threat and to learn lessons for future reference. A whole complex of neurochemical reactions is intended to leave us stronger and more resilient after dealing with a threat than before.  As philosopher Friedrich Nietzsche is credited with saying, "That which does not kill you makes you stronger."

 How can we tip the balance toward "stronger" and away from "dead"?  

 The difference between stress that harms and stress that helps is the level of dopamine found in the brain.  Dopamine is the key to focus, learning, and adaptation; it transforms stress from enemy into friend.  Optimal dopamine levels move us smoothly into problem-solving mode.  Too little of that critical hormone renders us helpless and passive; too much makes us freeze, like a deer in the headlights.  In both cases, we drown in a flood of damaging stress and cannot see our way out.

 Those critical dopamine levels are stabilized by physical activity.  The brain interprets increased muscular activity and heart rate as a sign that something's up.  In response, it produces the chemicals of arousal, focus, and learning.  In addition, activity diffuses the tendency toward panic and paralysis or aimless hyperactivity, achieving the balance that helps us make effective choices under pressure.

 Many of us know from experience that physical activity helps us manage stress. We also know (and, in my case, at this very moment) that the sudden shift from an active lifestyle to a sedentary one can wreak havoc with our mood.  I find it interesting and reinforcing to learn more about the neurobiology underlying my experience.  When I am tempted to give up and retreat to the couch, I envision the motivational "feel-good" hormones just waiting for me to move so we can get back on track and have some fun.