Understand this controversial concept and why why some experts say we shouldn’t slam it.
Coined in 1998, the phrase “adrenal fatigue” is used by some health care practitioners — typically in integrative and functional medicine — to refer to a collection of symptoms including fatigue and other general complaints, some of which mimic signs of adrenal diseases, syndromes and medical conditions.
A 2016 systemic review of adrenal fatigue literature, published in the journal BMC Endocrine Disorders, analyzed 58 studies that attempted to test for adrenal fatigue. Testing used in most studies included direct awakening cortisol, cortisol awakening response and salivary cortisol rhythm. Researchers found conflicting results and concluded there is no firm evidence that the condition exists; however, they also noted several limitations to the review, including heterogeneity of study design plus many study designs’ descriptive nature, the poor quality of the assessment of fatigue and the use of unsubstantiated methodology for cortisol assessment.
While no one disputes the existence of patients’ symptoms, many researchers and medical organizations, including the Mayo Clinic and Endocrine Society, have determined that adrenal fatigue is not a single condition or syndrome. Further, they have expressed concern with the lack of standardized language — which can sometimes include “burnout” or “burnout syndrome” — as well as the lack of clinical evidence to support testing.
However, many of those critics advise against telling patients that adrenal fatigue is a myth or that it doesn’t exist. Rather than fixating on a label, experts encourage practitioners to take patients’ complaints and symptoms seriously and investigate potential causes and treatments.
The Concept of Adrenal Fatigue
Symptoms associated with “adrenal fatigue” include fatigue, unexplained weight loss, low blood pressure and lightheadedness, darkening of the skin, loss of body hair, body aches, hormone imbalance, poor digestion, trouble falling asleep or waking up, reliance on caffeine to stay awake during the day, a lowered immune system and slow recovery from illness, inability to concentrate and a reduced ability to cope with stress.
The theory is that chronic physical or psychological stress creates subclinical adrenal dysfunction. (By definition, subclinical means not severe enough to be readily detectable or present definite symptoms.) This is due to a high burden on the adrenal glands to produce high levels of hormones long-term, namely cortisol, ultimately causing chronically low cortisol levels. In other words, the adrenal glands can’t keep up with the patient’s constant state of stress.
Although there are many known diseases and conditions that affect the adrenal glands, most are rare:
Primary adrenal insufficiency caused by insufficient steroid hormone production despite adequate adrenocorticotropic hormone (ACTH) levels. Low ACTH hormone levels are caused by a problem with the pituitary gland and are considered secondary adrenal insufficiency. Symptoms include fatigue, loss of appetite, low blood pressure, nausea and vomiting, dysregulation of blood glucose, darkening of the skin on the face and neck, and problems regulating stress management.
This disorder includes Addison’s disease and occurs when the adrenal glands do not make enough cortisol. Potential causes include stopping a steroid medication suddenly or an autoimmune disease. Symptoms include fatigue, muscle weakness, loss of appetite and abdominal pain.
Adrenal Crisis (AC)
A life-threatening condition requiring treatment with glucocorticoids, AC is caused by chronic adrenal insufficiency, Addison’s disease, tumors and severe infection or sepsis. Symptoms include abdominal pain, confusion or loss of consciousness, dehydration, fatigue and weakness, headache, fever and loss of appetite.
This is when there is too much cortisol in the blood stream due to exogenous sources such as steroids, or endogenous reasons, including an adrenal or pituitary gland tumor. Symptoms include weight gain, depression, muscle loss and weakness.
A condition in which the adrenal glands produce too much of the hormone aldosterone (causing hypertension and low blood potassium levels), it can be caused by hyperactivity in one or both adrenal glands, sometimes related to an adrenal tumor. Symptoms include high blood pressure, fatigue, headache, muscle weakness, low potassium levels and numbness.
Proponents say adrenal fatigue is a mild form of adrenal dysfunction. It’s also known as “subclinical adrenal insufficiency,” “adrenal stress,” “adrenal exhaustion,” “adrenal burnout” and “adrenal imbalance.” However, adrenal fatigue is not an accepted medical diagnosis
It’s important to understand the difference between adrenal insufficiency (a diagnosis that is recognized by the Endocrine Society) and adrenal fatigue. Some of the symptoms overlap, such as fatigue, low blood pressure and weight loss, while others do not. People with adrenal insufficiency often experience joint pain, nausea, vomiting, diarrhea and dry skin in addition to fatigue. Adrenal insufficiency is diagnosable by a physician through ACTH Stimulation and Insulin-Induced Hypoglycemia tests.
However, there are no scientifically validated tests to assess whether a patient is experiencing altered hormone levels that could indicate subclinical adrenal dysfunction. Tests that attempt to do so include any combination of salivary cortisol tests, DHEA-Sulfate serum test, thyroid hormone tests and a nonvalidated survey.
Proposed interventions for adrenal fatigue include moderate exercise, a balanced diet that supports proper blood sugar regulation, adequate sleep, and stress relief and management techniques. Some practitioners also recommend supplements, including B-vitamins, dehydroepiandrosterone (DHEA) and adaptogenic herbs or adaptogens — a collection of compounds used to stimulate non-specific resistance against physical, environmental and emotional stressors.
Other Potential Explanations
Critics of the adrenal fatigue concept believe its hallmark symptom, fatigue, may be related to other diseases or the presence of long-term stressors. For example, conditions that may mimic symptoms of adrenal fatigue include anemia, thyroid disease, growth hormone deficiency, depression, fibromyalgia and menopause, among others.
When clients or patients arrive with questions about adrenal fatigue, registered dietitian nutritionists can start by exploring symptoms, medical history and lifestyle factors during the nutrition assessment. Being aware of the different types of adrenal diseases (see sidebar) is important, as is referring back to their primary care provider if further medical testing is warranted.
In a 2018 commentary in the journal Endocrine Practice, one physician recommended patients who are concerned about “adrenal fatigue” undergo testing for adrenal disease. If the results are negative, they should seek lifestyle approaches to improve stress and promote wellness.
RDNs can educate clients and patients on the importance of stress management, a healthful diet and physical activity. And for those taking or considering supplements, RDNs can reinforce the importance of finding products that are third-party tested for safety, in addition to reviewing other medications, supplements and medical conditions for potential interactions.
Practicing patient-centered care is an important part of any therapeutic relationship — and it’s important to meet people who are seeking help with an open mind.
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