The majority of patients report some preceding moderate to serious physical stress (such as a chronic viral infection) or emotional event (often an episode of depression or chronic mental stress). Some experts theorize that such events, especially in people with certain neurological and genetic abnormalities, may overwhelm a person’s ability to regulate her own homeostatic self-regulating systems. I believe there is a great deal of truth to this idea (though admitting so may not endear me to those who believe that CFS is the result entirely of an infectious agent). I do believe that infectious agents can and do trigger CFS, but stress and infection go hand in hand. Stress weakens the body’s immune system, and an overtaxed immune system is quite stressful.
Some researchers are investigating abnormalities in CFS patients of the brain system known as the hypothalamus-pituitary-adrenal axis. This system produces or regulates hormones and brain chemicals that control important functions, including sleep, response to stress, and depression. It’s our self-regulating, homeostatic system. The HPA axis is a major part of the neuroendocrine system, which controls reactions to stress. It regulates various body processes such as digestion, the immune system, and metabolism, and it’s generally suppressed in CFS patients.
Low Cortisol Levels
A number of studies on CFS patients have observed deficiencies in cortisol levels, a stress hormone produced in the hypothalamus. Cortisol suppresses inflammation, increases stamina, boosts mental and physical energy, and coordinates cellular immune activation. Cortisol deficiency may be why CFS patients consistently demonstrate a severely compromised resiliency to stress. (Although stress is commonly thought of as resulting from emotional or psychological causes, certain infections may cause severe unrelenting internal biochemical stress.) As a diagnostic marker for CFS, however, individual cortisol levels aren’t useful.
Typically, the altered cortisol levels noted in CFS cases fall within the accepted range of normal, and only the average between cases and controls reveals a distinction.
Some of the symptoms of CFS, such as impaired cognition, may result from brain abnormalities. Several studies have reported significantly more abnormalities on MRI among CFS subjects relative to controls. Other studies have revealed lesions within the brains of CFS patients, and Single Photon Emission Computed Tomography (SPECT) scanning has repeatedly demonstrated a decrease of blood flow in the brain. In one study, decreased regional cerebral blood flow throughout the brain was observed in 80% of CFS patients! These observations may explain the “brain fog,” poor mental clarity, and fatigue associated with CFS. They might also demonstrate CFS’s association with oxidative (free radical) stress. Oxidative stress is a general term used to describe the level of damage to a cell, tissue, or organ caused by the reactive oxygen species (ROS) These very small, highly reactive molecules can affect any cell or system, including the brain. Most ROS come from normal internal bodily reactions, but external sources include first- and secondhand cigaret smoke, environmental pollutants, excess alcohol, asbestos, ionizing radiation, and bacterial, fungal, or viral infections. Supporting this oxidative-stress theory is the fact that antioxidant therapy has been proven helpful in the treatment of CFS. In one study involving CFS patients who required bed rest following mild exercise, 80% were deficient in Coenzyme Q10 (CoQ10), a potent antioxidant. After three months of supplementing with 100 mg. of CoQ10, 90% of the patients had a reduction or disappearance of clinically measured symptoms, and 85% had decreased post-exercise fatigue.
You can read more about CFS on my www.treatingandbeating.com site.