Cortisol is a glucocorticoid hormone produced in the adrenal glands, which sit atop both kidneys. Cortisol's primary function is to maintain energy levels and vital body functions when the body is under stress. Cortisol is released during the so-called "flight or fight" response of the sympathetic nervous system. The adrenal glands and pituitary gland can become fatigued by physical and emotional stress, diseases and dietary factors, which lead to low cortisol levels and disrupted metabolism, among other effects.
Functions of Cortisol
The adrenal cortex of the adrenal gland is stimulated by pituitary hormones to release cortisol. Cortisol helps maintain blood pressure and cardiovascular function, while suppressing the inflammatory response, healing processes and aspects of the immune system. Cortisol is also an important hormone for balancing metabolism as it helps stimulate the conversion of glycogen stores into glucose, which elevates blood sugar levels and provides energy. In essence, cortisol helps the body maintain necessary levels of energy to quickly deal with excessive stress. Unfortunately, stress is ubiquitous and continuous in many people's lives, which acts to fatigue the adrenal glands.
Causes of Low Cortisol
Excessive emotional and physical stress is the most common cause of temporary reduction in cortisol levels because the adrenal and pituitary glands eventually become fatigued and are unable to produce normal amounts of hormones. The most common disease leading to low levels of cortisol is Addison's disease, a disorder of the adrenal glands. Other causes of low levels of cortisol include adrenal or pituitary tumors, infections, inflammation from trauma, autoimmune response and drug interference or toxicity. Chronic caffeine consumption can also fatigue the adrenals and result in low cortisol secretion.
Low Cortisol and Metabolism
An insufficient amount of cortisol disrupts thyroid hormone production, which is the main gland in control of metabolism. A metabolism altered by low cortisol results in low blood sugar levels and reduced glycogen storage in the liver, which is used to quickly convert into glucose when a quick burst of energy is required. As such, the initial symptoms of low cortisol are much like those of diabetes, such as fatigue, lethargy, weakness, brain fog, headaches and gastrointestinal problems. Uncontrolled diabetes is characterized by high blood sugar levels, but not enough insulin to get the glucose into cells where it can be metabolized into energy. Low cortisol levels simply lead to not enough glucose in the blood for the cells to use, even in the presence of adequate insulin.
Other Effects of Low Cortisol
In addition to early symptoms of fatigue and weakness, low levels of cortisol also lead to a loss of appetite, weight loss, low blood pressure, dizziness, vomiting, diarrhea, dehydration and an inability to tolerate cold temperatures. Left untreated, lack of cortisol causes skin discoloration, compromised immunity, irritability, depression, abdominal and back pain, collapse of peripheral blood vessels and reduced cardiac output, which can become a medical emergency.
References
- "Advanced Nutrition: Macronutrients, Micronutrients, and Metabolism"; Carolyn D. Berdanier; 2009
- MayoClinic.com: Constant Stress Puts Your Health at Risk; Sept. 11, 2010
- "Human Biochemistry and Disease"; Gerald Litwack; 2008
- "Harrison's Principles of Internal Medicine"; A. Fauci, et al.; 2008
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