Fatigue is a feeling of tiredness,
exhaustion, or lack of energy. You may feel mildly fatigued because of
overwork, poor sleep, worry, boredom, or lack of exercise. Any illness, such as
a cold or the flu, may cause fatigue, which usually goes away as the illness
clears up. Most of the time, mild fatigue occurs with a health problem that
will improve with home treatment and does not require a visit to a
A stressful emotional situation may also cause fatigue.
This type of fatigue usually clears up when the
stress is relieved.
Many prescription and
medicines can cause weakness or fatigue. The use or
abuse of alcohol, caffeine, or illegal drugs can cause fatigue.
visit to a doctor usually is needed when fatigue occurs along with more serious
symptoms, such as increased breathing problems,
signs of a serious illness, abnormal bleeding, or unexplained weight loss or
Fatigue that lasts longer than 2 weeks usually requires a
visit to a doctor. This type of fatigue may be caused by a more serious health
problem, such as:
- A decrease in the amount of oxygen-carrying
substance (hemoglobin) found in red blood cells (anemia).
- Problems with the heart, such as
coronary artery disease or
heart failure, that limit the supply of oxygen-rich
blood to the heart muscle or the rest of the body.
disorders, such as
diabetes, in which sugar (glucose) remains in the
blood rather than entering the body's cells to be used for
- Problems with the thyroid gland, which regulates the way
the body uses energy.
- A low thyroid level (hypothyroidism) can
cause fatigue, weakness, lethargy, weight gain, depression, memory problems,
constipation, dry skin, intolerance to cold, coarse and thinning hair, brittle
nails, or a yellowish tint to the skin.
- A high thyroid level
(hyperthyroidism) can cause fatigue, weight loss, increased heart rate,
intolerance to heat, sweating, irritability, anxiety, muscle weakness, and
- Kidney disease and liver disease, which cause
fatigue when the concentration of certain chemicals in the blood builds up to