Adrenal glands function to produce hormones essential to life. The adrenal medulla is the inner portion of the adrenal gland, and produces adrenaline and noradrenaline. The adrenal cortex is the outer portion of the adrenal gland, and produces cortisol, estrogen, progesterone and testosterone. Cortisol regulates other hormones, balances metabolism and manages immune function. Chronic stress, such as that incurred by daily consumption of caffeine, creates a situation of sustained high levels of cortisol.
Stress results in healthy adrenal glands instantly releasing stored energy for fuel. This, in turn, increases heart rate and blood pressure, shuts down digestion and quickens reactions. Known as "fight or flight," this stress response function is instantaneous and short term, taking precedence over everything else.
Caffeine causes nerve cells in the brain and body to fire faster, increasing activity of the stress response system, just as stress does, notes the Women to Women website. Caffeine stimulates the adrenal glands to increase cortisol release. Cortisol then elevates heart rate and blood pressure, readying the body for a "fight or flight" response. Once the adrenals are provoked to release cortisol in such a manner over and over again, a decreased resistance to stress occurs, notes Women to Women.
Drinking one or more caffeinated beverages daily results in short-term energy and possible long-term fatigue. Caffeine puts the nervous and hormonal systems into a constant state of "flight or fight" stress response, depleting energy reserves. Women to Women notes that pushing the adrenal glands to extremes leads to fatigue, anxiety, insomnia and weight gain.
In addition, glucose, released from the liver, increases with caffeine use. This freed glucose gives people a sugar high quickly followed by a sugar crash, resulting in cravings for more caffeine or sugar in the from of simple carbohydrates. These sugar highs and lows add increased stress to the adrenal glands.
Chronic Adrenal Stimulation
Sustained adrenal stimulation from caffeine results in chronic high levels of cortisol, which breaks down healthy bone and muscle, slows down cellular healing, and interferes with digestion, metabolism and mental function, states Women to Women.
According to Dr. Lawrence Wilson, an expert on adrenal burnout, chronically pushing the adrenal glands with caffeine puts them into a slow decline. Individuals may use caffeine because they are already in adrenal burnout and are looking for energy. The caffeine only allows people to feel better temporarily while continuing to deplete their adrenals.
Indirect Effects on Hormonal Balance
Healthy adrenal glands maintain adequate levels of the sex hormones progesterone, testosterone and estrogen. According to Marcelle Pick, N.P., they cannot maintain these hormone levels when they are under attack by constant caffeine use. As caffeine disrupts the body's natural cortisol rhythm, it places the body in a constant state of emergency. This constant state of emergency depletes adrenal reserves, forcing the adrenals into survival mode levels of cortisol production only.