Causes of Extreme Fatigue & Muscle Aches

Almost everyone has some experience with fatigue and muscle aches as many conditions can cause these to symptoms to occur, including a new exercise routine. Generally these symptoms are not serious and resolve quickly without treatment, but extreme fatigue and muscle aches can be a sign of something serious in some instances. If these symptoms do not recede within a day or two or seem to progress, seek medical advice.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Fibromyalgia is a poorly understood chronic condition that affects virtually the entire body. It is characterized by a pain throughout the body and many patients report feeling that their aching muscles have been overworked or overstressed. The condition also causes multiple tender points throughout the muscles that can feel like knots. Other symptoms of fibromyalgia include:

  • trouble sleeping
  • headache
  • irritable bowel
  • dizziness
  • irritability
  • weakness
  • extreme fatigue

According to the Fibromyalgia Network, fibromyalgia affects between 3 and 5 percent of the population, is found in all age groups and is more common in women than men.


Systemic lupus erythematosus is an autoimmune disease that causes problems with multiple body systems and can affect each patient somewhat differently. Autoimmune diseases are caused by the body's own immune system attacking normal and healthy tissues because it perceives them as dangerous. According to the Lupus Foundation of America, Lupus is considered "the great imitator" because its symptoms imitate so many other conditions 1.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a condition characterized by severe fatigue and weariness that cannot be relieved by sleep 2. According to Medline Plus, an online resource of the National Institutes of Health, chronic fatigue syndrome commonly occurs in women ages 30 to 50 and usually is only diagnosed after other possible factors are ruled out by a doctor 2. Symptoms of the syndrome include:

  • extreme fatigue lasting six months or more that is severe enough to restrict activity
  • difficulty concentrating
  • muscle ache
  • muscle weakness
  • mild fever
  • headaches

There is no cure for chronic fatigue syndrome and treatment revolves around managing symptoms 2.


Major clinical depression is a medical disease that causes symptoms in both the mind and body 3. Depression can leave those who suffer with it unable to function in normal daily life and cause feelings of worthlessness, unhappiness and irritability. It is a chronic disease that requires long-term medical management and often is treated using multiple medications. Other symptoms of the disease include otherwise unexplained muscle achiness, back pain, severe fatigue, insomnia and change in appetite, according to 3.cause:

  • Other symptoms of the disease include otherwise unexplained muscle achiness
  • back pain
  • severe fatigue
  • insomnia
  • change in appetite
  • according to 3