The adrenal glands are located on top of the kidneys and are part of the endocrine, or glandular, system of the body. Like all glands, the adrenals are sensitive to stress and a variety of dietary chemicals, which affect hormonal secretions. Some chemicals, such as caffeine, can over-stimulate the adrenals to release excessive amounts of hormones, which leads to adrenal fatigue or exhaustion. Caffeine is a widely consumed drug in the United States, most commonly through drinking coffee, tea and soda pop, but also through eating chocolate and taking medications.
The Adrenal Glands
The bean-shaped adrenal glands produce a variety of hormones that regulate energy production, fluid balance and immune functions, among other essential functions. In general, they help the body deal with stress by adjusting biochemical factors in what has been called the "fight-or-flight" response. According to the "Textbook of Medical Physiology," the adrenal cortex secretes steroids that regulate body fluids, mediate the effects of stress and reduce inflammation. It also releases sex hormones, such as estrogen, progesterone and testosterone. The adrenal medulla secretes adrenalin and noradrenalin, which regulate energy and also mediate the effect of stress.
Effects of Caffeine
Caffeine suppresses the actions of adenosine, a neurotransmitter in the brain. Suppression of adenosine dramatically increases neural activity in the brain, which leads to a temporary increase in mental alertness, while reducing drowsiness and fatigue, according to "Biochemical, Physiological and Molecular Aspects of Human Nutrition." These effects are temporary and not related to energy metabolism, although sugars in soda pop and coffee products can boost energy levels short-term. The excess neuron activity caused by caffeine triggers the pituitary gland to signal the adrenals to secrete cortisol and adrenalin. Adrenalin is the primary source of the fight-or-flight response, which is meant to be reserved for quickly dealing with danger or severe stress. Put simply, caffeine puts the body under a continual state of stress that it is unable to resolve.
Caffeine and Adrenal Fatigue
The constant stimulating of stress hormones caused by caffeine is called "caffeinism" by some health professionals and is characterized by fatigue, anxiety, mood swings, insomnia, irritability and mild depression, as cited in "Biochemistry of Human Nutrition." After many months of chronic caffeinism, the adrenals can become severely fatigued or exhausted because caffeine forces the glands to secrete cortisol and adrenalin even when they don't have much left to give. Adrenal exhaustion symptoms include profound fatigue, difficulty relaxing, high anxiety, confusion, disrupted sleep cycles, disturbing dreams, salt and sugar cravings, low blood pressure, heart palpitations, reduced immunity, excessive allergic reactions, blood sugar imbalances, inflammation, difficulty breathing and tension headaches, according to "Human Biochemistry and Disease." People suffering from adrenal fatigue often have dark circles under their eyes, a quivering tongue, "pulsing" pupils and complain of being "burned out" or having frayed nerves.
Other Factors in Adrenal Fatigue
Although chronic consumption of moderate to high levels of caffeine contributes to adrenal fatigue, other factors are also important. Stress from work issues, financial problems, emotional trauma, infections, malnutrition and toxins from smoking, drugs, alcohol and highly refined sugars all contribute to adrenal fatigue, which has become nearly endemic in modern societies.
References
- "Textbook of Medical Physiology -- Tenth Edition"; Arthur C. Guyton et al; 2000
- "Biochemical, Physiological and Molecular Aspects of Human Nutrition"; Martha Stipanuk; 2006
- "Biochemistry of Human Nutrition"; George Gropper; 2000
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
