I believe that for most of us pain and fear are closely linked. Are they locked together? All recent attempts by scientists to define pain include reference to emotion. Imaging studies of the brain have shown a very close anatomical connection between parts of the brain activated by fear and those by pain.

Fear and pain cause the same physiological reactions: elevated adrenaline and other hormone changes, higher blood pressure, increased heart rate, shifts in circulation, greater muscle tension and changes in blood components may all occur. Central nervous system reactions may include visual disturbances, decreased fine motor control (e.g. the ability to use one’s hands for delicate work), cognitive dysfunction (i.e. increased difficulty thinking) and sensory disturbances.

These physiological reactions are what constitute stress. They define what occurs in the human being under acute stress. But human beings are built to adapt. When stress is chronic, many of the above reactions may return to normal or nearly normal levels – with emphasis on the word nearly. Adaptation is rarely perfect. In chronic pain patients, blood pressure and resting heart rate are often normal but psychological and cognitive problems are quite common. The same is true in patients with chronic anxiety.

There is a price to be paid for adaptation. Research has shown that chronic stress has long term consequences. A lowered ability to resist disease (immune system dysfunction), hypertension, cardiovascular disease, gastrointestinal problems, central nervous system changes and psychological disturbances are more prevalent in people with chronic stress.

Given that in most of us pain causes fear, it would seem that chronic pain patients get a double dose of chronic stress. However, despite everything I have just written, I believe that the chain that binds fear and pain may be broken or at least weakened. How this might be possible will be the subject of the next post.