Stress is the sum total of all mental and physical input over a given period of time. The marker used to measure stress is the adrenal steroid hormone, cortisol. Stress, whether physical or emotional in origin, provokes a response by the adrenal glands. Many hormonal imbalances are the direct result of adrenal insufficiency.
The adrenal glands produce two primary hormones, DHEA and cortisol. Both are considered the major shock absorber hormones in the body. They buffer stress and the negative impact it can have on both mental and physical function. Long-term stress can have a serious impact on the adrenal glands and cause them to shrink and reduce production. This causes cellular damage, which sets off a chain reaction affecting all parts of the body, as well as accelerating the aging process.
The symptoms associated with adrenal dysfunction are diverse and can involve the digestive, circulatory, respiratory, as well as the brain and nervous systems. In addition, the adrenals can impact the growth and repair of bones, muscles, hair and nails. Research has shown that to cause a positive hormonal change, you must first normalize adrenal activity.
Cortisol is a steroid hormone made in the adrenal glands. Cortisol's important function in the body includes roles in the regulation of blood pressure and cardiovascular function as well as regulation of the body's use of proteins, carbohydrates, and fats. Cortisol secretion increases in response to any stress in the body, whether physical (such as illness, trauma, surgery or temperature extremes) or psychological pressures, (such as poor marriage, unemployment, etc.).
When cortisol is secreted, it causes a breakdown of muscle protein, leading to release of amino acids into the bloodstream. These amino acids are then used by the liver to synthesize glucose for energy, in a process called gluconeogenesis. Cortisol also leads to the release of energy source from fat cells, for use by the muscles. Taken together, these energy directing processes prepare the individual to deal with stressors and insure that the brain receives adequate energy sources.
The body possesses an elaborate feedback system for controlling cortisol secretion and regulating the amount of cortisol in the bloodstream. The pituitary gland, a small gland at the base of the brain, makes and secretes a hormone known as adrenocorticotropic hormone, or ACTH. Secretion of ACTH signals the adrenal glands to increase cortisol production and secretion. The pituitary, in turn, receives signals from the hypothalamus of the brain in the form of the hormone CRH, or corticotrophin-releasing hormone, which signals the pituitary to release ACTH. Almost immediately after a stressful event, the levels of the regulatory hormones ACTH and CRH increase, causing an immediate rise in cortisol levels. When cortisol is present in adequate, or excess amounts, a negative feedback system operates on the pituitary gland and hypothalamus, which alerts these areas to reduce the output of ACTH and CRH, respectively, in order to reduce cortisol secretion when adequate levels are present.
DHEA (dehydroepiandrosterone) is the most abundant hormone found in the bloodstream. When the adrenal glands are chronically stressed, your production of DHEA can be greatly reduced. DHEA is an important regulator of the thyroid and pituitary glands. Though the adrenal glands produce most of the body's supply of DHEA, the gonads (ovaries, testes) can also manufacture DHEA when the adrenals are overworked. DHEA exerts powerful effects throughout the body. Most cells possess DHEA receptors on their membranes. DHEA is vital to health. DHEA also regulates many other hormones; however it can be easily converted to estradiol and/or testosterone and therefore needs to be monitored by testing levels of estradiol and testosterone. DHEA is a good stress barometer, because when stress levels go up, DHEA levels go down. Generally, DHEA levels tend to decrease with age. DHEA peaks at age 25 then declines at a rate of about 2% per year. It is not until the 40s that we begin to feel the effects of lower DHEA levels.
The most accurate way to measure DHEA is to measure it in the stable form that the body keeps it in: DHEA-S (dehydroepiandrosterone sulfate). Measurement of serum DHEA-S is a useful marker of adrenal androgen synthesis. Abnormally low levels have been reported in hypoadrenalism, while high or inverted diurnal levels have been reported in several conditions.