As a Neurologist, I’ve always been intrigued by the design of the Autonomic Nervous System or ANS, as we call it. It began to evolve about 500 million years ago, when fish began to develop body organs and a system was needed to automatically regulate their function. The ANS is absolutely brilliant. It is the master computer of all of the bodies’ automatic functions. It is divided into two main divisions; the sympathetic division know for delivering the ability to fight or flee in the presence of danger, and the parasympathetic division known for rest and rejuvenation. As you can see, these divisions are like two ends of a see saw. When one is high the other is low in terms of activity.
Sleep and Stress levels are probably the 2 most important functions regulated by the parasympathetic division. Clearly, the main purpose of sleep and relaxation is rest and rejuvenation. This function is regulated by a number of centers located in the brainstem. Activity from these centers impacts almost all of the bodily processes promoting healing effects. It also sends signals up into the brain to cause it to rest, particularly during deep or delta sleep. The parasympathetic division also causes dream or rapid eye movement sleep, allowing for the brain to resolve emotional issues and to solve problems.
Stress, on the other hand, does not originate in the ANS. Stress originates in the thinking brain, the cerebral cortex, and it sends signals down to the sympathetic division of the ANS, which also resides in the brainstem and prepares the body’s organs to function in a fight or flight mode. If you are in a life threatening situation, you need to be prepared to defend yourself or run. That is the main function of the sympathetic division, to ensure your survival. Unfortunately, the sympathetic division is also engaged due to chronic unhealthy stress, which definitely does not ensure your survival and instead leads to poor health and suffering. There are two distinctly different forms of stress – healthy stress and chronic unhealthy stress. We’ll cover that next.
