In 1905 Edmund Jacobson studied the “startled” reaction to unexpected loud noise. He learned that relaxed people had no obvious startled response to loud noises. Our entire system reacts within less than one second. Within milliseconds, our body can prepare for fight or flight. PMR involves tensing a set of muscles and then relaxing them. The technique works on the idea that once you identify the sensation of tension, you can relax it away. You find a tense spot, tense it even more, then relax it, creating a momentum that will cause your muscles to relax more deeply.
You will relax as much as you tense, like a pendulum swinging from side to side. The relaxation will be deeper because of this momentum when compared to just relaxing your muscles without tensing first. Your tense muscles send a message to your brain alerting your hormonal alarm system, and the autonomic nervous system, which is responsible for your protection and survival. You may be tense because you are stressed or you may be stressed because you are tense. It doesn’t matter. Learning to loosen up your body will make a big difference. Gripping, clenching, tightening muscles may prepare you to escape or to attack, but they make you tired as well, and may cause pain.
Herbert Benson, a Harvard University cardiologist and director of the mind/body medical institute, made a significant breakthrough in the 1970s. His studies revealed that we have an innate ability to reduce our heart rate, blood pressure and brain-wave activity, a process he called the “relaxation response,” a mirror image of the stress response. Relaxation engages the parasympathetic system -our rest and restore system- to reduce arousal. Our sympathetic system is concerned with the fight-flight response -the opposite of relaxation.
Our bodies are always searching for allostasis: The ongoing adaptive efforts of the body to maintain stability (homeostasis) in response to stressors. Like a thermostat in a room turning on and off when it reaches the desire temperature. Picture a car with the gas pedal pushed all the way down, while the brake is on! That is your body when you are stuck in a chronic stress response; unable to release the gas pedal, unable to experience your rest and restore response.