What is chronic fatigue syndrome (CFS)?

CFS shares symptoms with a number of other conditions including diabetes, thyroid disease, depression, anxiety, and substance abuse. The disease was not so long ago dismissed as the "yuppie flu," but it has gradually gained legitimacy and is now accepted as an established diagnosis. The Centers for Disease Control (CDC) developed a set of diagnostic criteria in 1994, and the agency has started tracking cases and reports that as many as 4 million Americans suffer from CFS.

Chronic fatigue and immune dysfunction syndrome (CFIDS or CFS) is a group of symptoms associated with severe, almost unrelenting fatigue. The main symptom is fatigue that results in constant and substantial reduction in your activity level. Oddly, despite their constant exhaustion, people with CFS typically find that they can't sleep.

CFS can begin gradually, usually following a period of severe physical or emotional stress. It can also begin suddenly, feeling like a "drop dead flu" that you can't fully recover from. Other common symptoms may include:

-  Insomnia
-  Achiness
-  Forgetfulness
-  Brain fog
-  Increased thirst
-  Bowel disorders
-  Recurring infections
-  Easily exhausted
-  Weight gain
-  Low libido

CFS's sister illness, fibromyalgia syndrome (FMS or FM), is characterized by muscle pain - sometimes all over the body, or sometimes only in specific areas. These painful areas can be transient or persistent. FM pain is caused by a shortening, or tightening of the muscles. These muscles need sleep and nutrition, among other things, in order to heal. Since CFS/FM sufferers rarely sleep well, these muscles stay knotted and painful. For most sufferers, CFS and FM are the same illness. However, some people have fatigue without pain, whereas others have pain without fatigue.

Hypothalamic dysfunction. The hypothalamus is the body's master gland and can be likened to the main circuit in your home's breaker box. The hypothalamus is weakened by long term exposure to physical or emotional stress, which will cause it to "blow." When the main fuse blows, all of the systems regulated by the hypothalamus malfunction. These systems include the glands (affecting the thyroid, adrenals, and sex hormones), the autonomic system (which regulates body temperature, blood pressure, and the anti diuretic hormone), and the sleep center.

People with CFS/FM typically suffer from a combination of different problems. The pattern can include infections (viral or bacterial), insomnia and hormonal problems, a combination I refer to as the "autoimmune triad." Other possible underlying issues include immune system dysfunction, mild chronic low blood pressure, low blood sugar (hypoglycemia), and iron deficiency anemia.

Chronic fatigue syndrome (CFS) describes a medical condition that involves severe fatigue lasting at least 6 months that can't be explained by other health problems or depression. People with CFS also complain of typical fibromyalgia symptoms, including pain, sleep problems, and poor concentration or a clouded memory. Chronic fatigue syndrome affects approximately 2% of adults in the United States, Europe, and South America.

Many experts consider feeling sick or exhausted after exercise -- called post-exertional malaise or fatigue -- to be a key feature of CFS. Often these symptoms last for 24 hours or longer after completing exercise. In some cases, post-exercise fatigue may not begin until a day or more after exercise. Criteria adopted in Canada consider fatigue, post-exertional malaise or fatigue, sleep disturbance, and pain to be the key features of CFS. Furthermore, a study published in Rehabilitation Psychology found post-exertional malaise to be the most important factor for identifying people with CFS.

Chronic fatigue syndrome means that you feel so tired that you can no longer do your normal daily activities. There are other symptoms too, but being very tired for at least 6 months is the main one. Many people improve in a year or two. Some people continue to have severe fatigue and other symptoms for many years.