Related Terms

Common terms used in relation to CFS

Burnout (as used here to relate to Chronic Fatigue Syndrome) seems to share lots of sets of symptoms with a variety of illnesses (as defined by the medical literature). Here are a few worth noting, with their formal definitions, as well as some key medical terms:

Chronic Fatigue Syndrome (Burnout)

Chronic Fatigue Syndrome (CFS), is a complex, chronic illness primarily characterized by extreme fatigue. The medical community’s understanding of CFS has evolved over time, and while its exact cause remains unknown, it is recognized as a serious condition that can severely impact the quality of life. Here is an overview including its medical definition:

  1. Primary Symptom – Severe Fatigue: The most prominent symptom of CFS is a fatigue that is profound, not improved by rest, and not due to ongoing exertion. This fatigue significantly impairs daily activities and functions.
  2. Medical Definition: CFS is defined by the presence of unexplained persistent or relapsing chronic fatigue for six months or more. This fatigue is not due to ongoing effort, not significantly alleviated by rest, and results in a substantial reduction in previous levels of occupational, educational, social, or personal activities.
  3. Post-Exertional Malaise (PEM): Patients with CFS often experience a worsening of their symptoms following physical or mental exertion, known as post-exertional malaise. This exacerbation can occur immediately or be delayed, and recovery can take disproportionately longer than would be expected.
  4. Additional Symptoms: In addition to severe fatigue, CFS is often accompanied by other symptoms such as muscle pain, joint pain without swelling or redness, headaches of a new type or severity, unrefreshing sleep, and cognitive impairments (like memory or concentration issues). There can also be tender lymph nodes, sore throat, and new sensitivities to foods, odors, chemicals, or noise.
  5. Diagnosis: There’s no single test to diagnose CFS. It’s usually a diagnosis of exclusion, meaning doctors must rule out other potential causes of fatigue before confirming a CFS diagnosis. This process includes evaluating the patient’s medical history, conducting physical exams, and performing various laboratory tests.
  6. Etiology (Causes): The cause of CFS is still not fully understood. Possible triggers identified include viral infections, immune dysfunction, abnormal stress responses, hormonal imbalances, and genetic predisposition. It’s likely that multiple factors contribute to the development of the syndrome.
  7. Management and Treatment: Treatment for CFS is mainly symptomatic and supportive. It includes a combination of pharmacological treatments for pain, sleep disturbances, and other specific symptoms, and non-pharmacological approaches like cognitive-behavioral therapy (CBT), graded exercise therapy (GET), and pacing techniques to manage energy.
  8. Prognosis: The course of CFS varies from patient to patient. Some people may recover over time, while others may experience symptoms for many years. The level of disability can also fluctuate, and a full recovery is possible but not common.
  9. Controversies and Challenges: CFS has been a subject of much debate and controversy, primarily due to the lack of understanding of its causes and the absence of objective diagnostic tests. Patients often face challenges in having their condition recognized and properly managed.

In summary, Chronic Fatigue Syndrome is a serious, long-term illness that affects multiple systems in the body. Due to its complex nature, management requires a comprehensive and individualized approach. Continued research and greater awareness are key to improving care and outcomes for those affected by this condition.

Myalgic Encephalomyelitis (ME)

Myalgic Encephalomyelitis (ME) is a chronic, complex, and often debilitating disease. It’s characterized primarily by severe, persistent fatigue and a range of other symptoms. ME is sometimes used interchangeably with Chronic Fatigue Syndrome (CFS), but there are technical distinctions between the two, particularly in the medical definitions and diagnostic criteria used.

Myalgic Encephalomyelitis (ME):

  1. Medical Definition: ME is defined as an acquired complex disorder characterized by a variety of neurological symptoms and signs, muscle pain with intense physical or mental exhaustion, relapses, and specific cognitive disabilities.
  2. Primary Symptom – Neurological Impairment: ME is distinguished by significant neurological impairments. These include cognitive dysfunction, muscle pain, and symptoms indicative of neurological disturbances like sensitivity to light and sound, sleep disturbances, and problems with memory and concentration.
  3. Post-Exertional Neuroimmune Exhaustion (PENE): This is a key feature of ME. It’s a marked, rapid physical and/or cognitive fatigability in response to exertion, which can be either physical, cognitive, or emotional. This symptom is more specifically defined in ME than the broader post-exertional malaise (PEM) associated with CFS.
  4. Diagnosis: Diagnosis of ME is based on specific criteria that emphasize neurological and immune manifestations. The Canadian Consensus Criteria (CCC) and the International Consensus Criteria (ICC) are commonly used for diagnosis and are more stringent than those for CFS.

Differences between ME and CFS:

  • Focus on Neurological Symptoms: ME places a greater emphasis on neurological symptoms and the specific nature of post-exertional neuroimmune exhaustion.
  • Diagnostic Criteria: The criteria for ME (like the CCC and ICC) are more specific and stringent, focusing on neurological, immunological, and energy metabolism impairments. In contrast, CFS criteria (like Fukuda and IOM) primarily focus on chronic fatigue and a broader range of symptoms.
  • Historical and Conceptual Origins: ME has a longer history, originally described in the 1950s, with a focus on neurological dysfunction. CFS was defined later, with a broader focus on chronic fatigue.

While these differences exist, in practice, the terms ME and CFS are often used interchangeably, and the conditions are frequently grouped together as ME/CFS. This overlap is partly due to similarities in symptoms and the challenge of distinguishing between them based solely on symptomatology, especially in the absence of definitive biomarkers. There’s ongoing debate and research within the medical community to better understand and delineate these conditions.

Adrenal Fatigue

Adrenal fatigue is a term that was originally used to describe a belief that the adrenal glands, which are responsible for producing stress hormones, become unable to function properly due to chronic stress. However, it’s important to note that “adrenal fatigue” is not a medically recognized condition. There is no scientific evidence to support the theory that long-term mental, emotional, or physical stress drains the adrenal glands and causes many common symptoms. Here’s an overview of the concept and the skepticism around it:

  1. Proposed Concept: The theory behind adrenal fatigue suggests that prolonged exposure to stress could lead to an overtaxing of the adrenal glands, eventually leading to a decreased ability to produce cortisol, the body’s primary stress hormone. Proponents believe this reduction in cortisol production leads to a variety of nonspecific symptoms.
  2. Symptoms Attributed to Adrenal Fatigue: These are generally nonspecific and can include tiredness, fatigue, sleep disturbances, digestive problems, body aches, nervousness, and cravings for salt and sugar. The issue, however, is that these symptoms can be associated with many other health conditions, making the concept of adrenal fatigue very controversial.
  3. Lack of Medical Recognition: The mainstream medical community does not recognize adrenal fatigue as a legitimate medical diagnosis. This is largely because there is no scientific evidence supporting the idea that prolonged stress leads to adrenal exhaustion. The symptoms attributed to adrenal fatigue are often vague and non-specific, making them attributable to a wide range of other conditions.
  4. Adrenal Insufficiency: In contrast to adrenal fatigue, adrenal insufficiency is a recognized medical condition. It occurs when the adrenal glands produce insufficient amounts of hormones, including cortisol. This condition is diagnosed through biochemical laboratory tests and requires medical treatment. Adrenal insufficiency can be serious and is a distinctly different condition from the proposed idea of adrenal fatigue.
  5. Criticism from Medical Experts: Medical experts and endocrinologists criticize the concept of adrenal fatigue for lacking scientific backing and for potentially leading to misdiagnosis or overlooking of serious underlying conditions. They caution against attributing a wide array of symptoms to a disorder that has not been scientifically validated.
  6. Alternative Views: Some practitioners in alternative medicine continue to support the concept of adrenal fatigue and offer various treatments for it, including dietary changes, supplements, and lifestyle modifications. However, these treatments are not based on solid scientific evidence.

In summary, while adrenal fatigue is a popular concept in some circles, it is not recognized in conventional medicine due to a lack of scientific evidence supporting it. If someone is experiencing symptoms often attributed to adrenal fatigue.


Fibromyalgia is a chronic condition characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues. It’s recognized by the medical community as a distinct disorder, often associated with a heightened sensation of pain due to abnormalities in how the brain processes pain signals.

Medical Definition of Fibromyalgia:

  1. Widespread Pain: One of the primary symptoms of fibromyalgia is a persistent, widespread pain throughout the body, often described as a constant dull ache that has lasted for at least three months. The pain typically occurs on both sides of the body and above and below the waist.
  2. Tender Points: Patients with fibromyalgia often have tender points on their bodies, specific places on the neck, shoulders, back, hips, arms, and legs that hurt when pressure is applied.
  3. Fatigue and Sleep Disturbances: People with fibromyalgia often wake up tired, even after sleeping for long periods. Sleep is frequently disrupted by pain, and many patients have other sleep disorders, such as restless legs syndrome or sleep apnea.
  4. Cognitive Difficulties: A symptom commonly referred to as “fibro fog” impairs the ability to focus, pay attention, and concentrate on mental tasks.
  5. Co-occurring Symptoms: Many individuals with fibromyalgia also experience depression, anxiety, headaches, irritable bowel syndrome, numbness or tingling in the hands and feet, and sensitivity to temperature, lights, and sounds.

How Fibromyalgia Differs from Chronic Fatigue Syndrome (CFS):

  1. Primary Symptoms: The primary symptom of fibromyalgia is widespread musculoskeletal pain, whereas CFS is primarily characterized by chronic, debilitating fatigue.
  2. Pain Focus: In fibromyalgia, the pain is more specific to muscle and connective tissue pain, with identifiable tender points. In CFS, while pain can be a symptom, it is not as widespread or as significant as in fibromyalgia.
  3. Fatigue and Energy Levels: While both conditions involve fatigue, the fatigue in CFS is typically more pronounced and debilitating. CFS patients often experience post-exertional malaise, a severe worsening of symptoms following physical or mental exertion, which is less emphasized in fibromyalgia.
  4. Diagnostic Criteria: Fibromyalgia and CFS have different diagnostic criteria. For fibromyalgia, diagnosis typically focuses on pain criteria and the presence of other symptoms like fatigue, sleep disturbances, and cognitive issues. In contrast, CFS diagnosis heavily weighs on the persistent and unexplained nature of fatigue.
  5. Overlap in Symptoms: There is significant symptom overlap between the two conditions, and it is possible for an individual to have both fibromyalgia and CFS.

Both conditions are not fully understood, and their causes are believed to be multifactorial, including genetic predisposition, infections, physical or emotional trauma, and other triggers. Treatment for both fibromyalgia and CFS typically involves a combination of medication, physical therapy, and lifestyle modifications aimed at symptom management. The recognition of these conditions as legitimate medical diagnoses has grown, but there is still much to learn about their causes, relationships, and most effective treatments.

HPA Axis

The Hypothalamic-Pituitary-Adrenal (HPA) axis is a complex set of direct influences and feedback interactions among three components: the hypothalamus, the pituitary gland, and the adrenal glands. It plays a crucial role in the body’s response to stress and is also involved in various other bodily processes, including digestion, the immune system, mood and emotions, sexuality, and energy storage and expenditure.

Components of the HPA Axis:

  1. Hypothalamus: This brain region releases corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) into the bloodstream, which travel down to the pituitary gland.
  2. Pituitary Gland: In response to CRH and AVP, the pituitary gland secretes adrenocorticotropic hormone (ACTH) into the bloodstream.
  3. Adrenal Glands: ACTH prompts the adrenal glands to produce cortisol, a stress hormone. Cortisol, in turn, has several effects on the body, including suppressing the immune system and increasing blood sugar.
  4. Feedback Loop: The HPA axis works on a feedback loop. High levels of cortisol signal the hypothalamus and pituitary to reduce CRH and ACTH production, respectively.

Chronic Fatigue Syndrome (CFS) and the HPA Axis:

CFS has been associated with dysregulation of the HPA axis, although the exact nature of this relationship is still not fully understood. Key points include:

  1. Lowered Cortisol Levels: Some research has shown that individuals with CFS may have lower than normal cortisol levels, which is suggestive of an underactive HPA axis. This hypoactivity could be a result of chronic overstimulation due to prolonged stress, eventually leading to a kind of burnout.
  2. Blunted HPA Axis Responsiveness: Patients with CFS often exhibit a reduced responsiveness of the HPA axis to stress. This diminished response could contribute to the chronic fatigue and other symptoms experienced, as cortisol is involved in energy production and stress response.
  3. Impact on Immune System: Since cortisol helps regulate the immune system, abnormalities in the HPA axis could contribute to the immune dysfunction observed in some CFS patients, such as increased susceptibility to infections and a pro-inflammatory state.
  4. Altered Diurnal Rhythm of Cortisol: Some CFS patients have an altered diurnal rhythm of cortisol secretion, which could explain some of the sleep disturbances and other circadian rhythm-related symptoms seen in CFS.
  5. Consequence or Cause: It’s still debated whether HPA axis dysregulation in CFS is a consequence of the illness (due to prolonged illness stress, for example) or a contributing factor to its development.
  6. Feedback to Brain Regions: Changes in cortisol levels can feedback to affect the hypothalamus and other brain regions, potentially contributing to the cognitive and mood disturbances often seen in CFS.

Understanding the role of the HPA axis in CFS is an area of ongoing research. This research is significant because if HPA axis dysregulation plays a key role in CFS, it could open the door to new therapeutic targets, including ways to normalize HPA axis function as a means of alleviating some symptoms of CFS.