Fatigue: Causes and Remedies

Fatigue

Fatigue is generally defined as a feeling of lack of energy and motivation that can be physical, mental or both. Fatigue is not the same as drowsiness, but the desire to sleep may accompany fatigue.

Apathy is a feeling of indifference that may accompany fatigue or exist independently. In addition, individuals often describe fatigue using a variety of terms including weary, tired, exhausted, malaise, listless, lack of energy and feeling run down.

Fatigue is common. About 20% of Americans claim to have fatigue intense enough to interfere with living a normal life.

A physical cause has been estimated to be responsible 20% to 60% of the time, while emotional or mental causes comprise the other 40% to 80% of cases of fatigue. Unfortunately, fatigue can also occur in normal individuals that experience intense physical or mental activity (or both).

However, in contrast to fatigue that occurs with some diseases and syndromes, normal fatigue in healthy individuals is quickly relieved in a few hours to about a day when the physical or mental activity is reduced.

Also, people occasionally experience fatigue after eating (sometimes termed postprandial depression) which can be a normal response to food, especially after large meals and this may last about 30 minutes to several hours.

In addition to the many terms attributed to "fatigue", there are further problems with the terminology used to describe fatigue.

There are several "fatigue syndromes" that occasionally appear in the medical literature. For example, Epstein-Barr chronic fatigue syndrome, post viral infection fatigue syndrome, and adrenal fatigue syndrome are among the most commonly seen.

However, many physicians do not recognize these as syndromes because the criteria used to define them as syndromes are too diffuse and many consider the associated fatigue (sometimes chronic fatigue) as either a symptom or complication of the underlying associated diseases.

However, there is a well-defined chronic fatigue syndrome recognized by specific criteria. Basically, two sets of criteria need to be met to establish a diagnosis of chronic fatigue syndrome:

1. Have severe chronic fatigue for at least six months or longer with other known medical conditions (whose manifestation includes fatigue) excluded by clinical diagnosis; and
2. Concurrently have four or more of the following symptoms:

• post-exertional malaise
  
• impaired memory or concentration
  
• unrefreshing sleep
  
• muscle pain
  
• multi-joint pain without redness or swelling
  
• tender cervical or axillary lymph nodes
  
• sore throat
  
• headache

Consequently, people and their health care practitioners need to spend some time together to clearly determine whether or not the problem or symptom is truly fatigue, and if it is, any associated symptoms that may accompany the fatigue should be explored.

Fatigue Causes

The potential causes of fatigue are numerous. The majority of diseases known to man often list fatigue or malaise as possible associated symptoms.

This is complicated by the fact that fatigue can occur in normal healthy individuals as a normal response to physical and mental exertion.

However, normal fatigue may begin to become abnormal if it becomes chronic, extreme or prolonged fatigue; usually this occurs when a person experiences chronic or prolonged physical or mental exertion.

For example, unusually hard physical or mental exertion for one day can result in normal fatigue that may last about a day or sometimes more, depending on the exertion level, while daily unusually hard physical or mental exertion may result in prolonged fatigue (usually greater than 24 to 48 hours). This latter situation may develop into abnormal fatigue.

The causes of fatigue can be classified under several broad disease entities or lifestyle problems that have fatigue as an associated symptom. The following table categorizes numerous causes of fatigue. This table is not meant to be all inclusive.

The following table summarizes some common causes of fatigue but is not meant to be comprehensive:

Common Causes of Fatigue
Metabolic/ Endocrine	anemia; hypothyroidism; diabetes; electrolyte abnormalities; kidney disease; liver disease; Cushing's disease
Infectious	infectious mononucleosis; hepatitis; tuberculosis; Cytomegalovirus; HIV infection; influenza (flu); malaria and many other infectious diseases
Cardiac (heart) and Pulmonary (lungs)	congestive heart failure; coronary artery disease; valvular heart disease; chronic obstructive pulmonary disease (COPD); asthma; arrhythmias; pneumonia
Medications	antidepressants; anti-anxiety medications; sedative medications; medication and drug withdrawal; antihistamines; steroids; some blood pressure medications; some antidepressants
Psychiatric (Mental Health)	depression; anxiety; drug abuse; alcohol abuse; eating disorders (for example; bulimia; anorexia); grief and bereavement
Sleep Problems	sleep apnea; reflux esophagitis; insomnia; narcolepsy; work shift work or work shift changes; pregnancy; extra night hours at "work"
Other	cancer; rheumatology illnesses such as rheumatoid arthritis and systemic lupus; fibromyalgia; chronic fatigue syndrome; normal muscle exertion; obesity; chemotherapy and radiation therapy

Fatigue Symptoms

Fatigue, either mental or physical, is a symptom that usually has some underlying cause. Fatigue may be described by people in different ways, and may include some combination of the following (both mental and physical):

• weakness,
  
• lack of energy,
  
• constantly tired or exhausted,
  
• lack of motivation,
  
• difficulty concentrating, and/or
  
• difficulty starting and completing tasks.

Other symptoms such as fainting or loss of consciousness (syncope), near-syncope, rapid heartbeat (palpitations), dizziness or vertigo may also be described as part of the fatigue experienced by the affected individual. The presence of these symptoms may actually help lead a health care practitioner to discover the underlying cause(s) of the fatigue.