In any given situation as we perceive the world around us, the brain decides whether something is threatening or not. If threat is perceived, this causes a series of metabolic reactions triggered by the release of specific hormones, which shifts energy from long-term maintenance to short-term needs. The stress response is biphasic. The first phase consists of direct stimulation of the adrenal glands, the two small structures sitting on top of the kidneys by the hypothalamus in the brain. Though they are small in size, these glands pack a powerful punch. When stimulated by the hypothalamus, they immediately release the hormone epinephrine, or adrenalin. The epinephrine causes an increase in heart rate, increases the flow of oxygen to the brain, increases fibrinogen which enables the blood to clot faster, and increases energy production by directing the liver to break down glycogen into glucose and releasing fatty acids from fat stores. These actions together comprise the “fight or flight” reaction, in which we prepare ourselves for the perceived threat and either defend ourselves or flee. In either case, this first phase of the response with release of adrenalin prepares our body for either action.
The second phase of the stress response engages a pathway known as the Hypothalamic-Pituitary-Adrenal axis (HPA axis). In a series of intermediate steps engaging the brain (hypothalamus and pituitary gland) in which several intermediate hormones are released, the adrenal gland is stimulated to itself release the hormone Cortisol. Cortisol blocks the action of Insulin causing a relative hyperglycemia (high blood glucose) and shifting metabolic reactions toward production of fat and glycogen (the storage form of glucose). Cortisol also through this same mechanism can cause a loss of muscle protein as it breaks down muscle to use its amino acid components for energy. Since the action of insulin is blocked, glucose cannot get into the cells for energy and instead is stored as glycogen. Muscle breakdown ensues, ensuring an adequate supply of amino acids for energy. Cortisol also has a double edged effect on the immune system. In the short term it stimulates our immune system so that we are prepared for threats like infections, viruses, etc. In the long term however, cortisol suppresses the immune system.
This system evolved to serve us well in time of “fight or flight”. Whether the perceived threat is physical and external (head-on collision) or minute and internal (bacterial or viral infection) the response is activated. Once the threat is eliminated, the response is deactivated by internal feedback mechanisms.
Problems arise when this response does not dissipate as it should but becomes chronic and persists in causing harm on a cellular level. The world in which we live is a 24/7 activity. Our stress response is not only activated by a perceived threat but also by anticipation of a threat. It never dissipates as it should because humans have a tendency to anticipate and worry about the consequences of the perceived threat. This causes epinephrine and cortisol to remain in our systems at the cellular level causing disequilibrium in our metabolism and resulting is hypertension, heart disease, dementia, insomnia, obesity, decreased lean body mass and increased visceral and body fat. Epinephrine and cortisol are catabolic hormones which continue to “break down” metabolic processes. Since cortisol blocks the effect of Insulin, the “build-up” hormone, we find ourselves in a downward spiral resulting in a rapidity of aging and its consequences.
The need to control the mind and its stress response, to prevent the chronicity of this response, is essential to balancing our metabolism and achieving wellness. Deep breathing exercises, meditations and the use of herbal supplements can readily reduce the chronic aspect of this response and reverse the damage on a cellular level. Again, this aspect of the Metabolic Wellness Program is as equally important as the others and is intricately woven into the other elements discussed.