Persons most commonly affected: More often in women than men, and in people in their 40s and 50s.

Symptoms and indications: CFS patients may report many symptoms which are not included in all diagnostic criteria, including muscle weakness, cognitive dysfunction, hypersensitivity, orthostatic intolerance, digestive disturbances, depression, poor immune response, and cardiac and respiratory problems.

Causes and risk factors: Of all chronic illnesses, chronic fatigue syndrome is one of the most mysterious. Unlike definite infections, it has no clear cause. Several possible causes have been proposed, including: Depression; Iron deficiency anemia; Low blood sugar (hypoglycemia); History of allergies;
Virus infection, such as Epstein-Barr virus or human herpesvirus 6; Dysfunction in the immune system;
Changes in the levels of hormones produced in the hypothalamus, pituitary glands or adrenal glands; and Mild, chronic low blood pressure (hypotension).

The cause of chronic fatigue syndrome may be an inflammation of the pathways of the nervous system as a response to an autoimmune process, but with nothing measurable in the blood as in other autoimmune diseases, such as rheumatoid arthritis and lupus. Chronic fatigue syndrome may also occur when a viral illness is complicated by a dysfunctional immune system. Some people with CFS may have a low blood pressure disorder that triggers the fainting reflex.

In many cases, however, no serious underlying infection or disease is proved to specifically cause chronic fatigue syndrome. Lack of medical knowledge and understanding of CFS has made determining and describing the characteristics of the condition difficult.

Prevention: Physical activity performed at a comfortable pace is important for everyone to maintain good health. People with CFS need to learn how much activity is helpful and when to stop, so they do not increase their level of fatigue.

In general, people with CFS should pace themselves carefully and avoid excessive physical or emotional stress. Remember, the goal is to avoid increasing fatigue or pain. Maintain a regular and manageable daily routine to avoid a relapse or increase of symptoms. Exercise should be supervised by a knowledgeable health care provider or physical therapist.

Total rest should also be avoided as it may make your fatigue worse. You should maintain physical activity at a comfortable pace. If you increase your level of physical activity, do so gradually.

Decreased consumption of alcohol and caffeine at night may help you sleep.

Try to minimize social isolation.