Many medical conditions can cause both pain in the legs and fatigue, and determining the cause of these symptoms often requires a trip to the doctor. To make a diagnosis, your doctor needs a thorough understanding of your symptoms, including what brings them on, what improves them, and other symptoms you may have.

Is This an Emergency?

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


Overtraining is a type of overexertion that can cause both fatigue and muscle aches. It is usually seen in competitive athletes, but according to the June 2003 issue of "The Physician and Sports Medicine," it can occur in ordinary fitness enthusiasts who exercise intensely over an extended period of time. Overtraining may also affect someone who drastically increases their level of activity after a long period of inactivity. Other symptoms of overtraining may include irritability, insomnia, anxiety and increased susceptibility to infections.

Circulation Causes

Disorders that reduce blood flow to the legs can cause aching legs and fatigue. Peripheral artery disease (PAD) is one of the most common causes of decreased circulation in the legs. PAD is caused by atherosclerotic plaques that block arteries in the legs, similar to the plaques that block arteries of the heart in coronary artery disease. PAD classically causes leg pain while walking or climbing stairs, which improves with rest. People frequently notice an overall feeling of fatigue as well. PAD typically affects older individuals who are current or past cigarette smokers and who have other cardiovascular disease risk factors, such as high cholesterol and diabetes. PAD is particularly important because it is a sign of possible heart disease. People with PAD often have coronary artery disease as well.

Inflammatory Disorders

Disorders causing inflammation may produce pain in the areas of inflammation, as well as generalized symptoms such as fatigue or fever. Polymyalgia rheumatica is an inflammatory disorder that causes pain and stiffness in multiple muscles and joints 5. It can cause aching legs and fatigue. Other symptoms may include a mild fever, general feeling of being unwell, depression, loss of appetite and unintended weight loss. Polymyalgia rheumatica typically affects older people and is more common in those of northern European ancestry 5. It affects women more often than men. About 20 percent of people with polymyalgia rheumatica also have giant cell arteritis, according to a review article in the October 2017 issue of "The Lancet." This is a serious inflammatory disorder affecting arteries 5. Temporal arteries -- located on each side of the forehead -- are often involved, leading to headaches, jaw pain, vision changes and sometimes blindness or a stroke.

Fibromyalgia and Chronic Fatigue Syndrome

Fibromyalgia and chronic fatigue syndrome (CFS) are two related disorders 2. Fatigue, headaches, muscle aches and sleep disturbance are among the symptoms common to both disorders. In fibromyalgia, pain symptoms tend to be more prominent, whereas in CFS, fatigue and flu-like symptoms are more obvious. Depression is quite common with both disorders, and treating this depression may improve other symptoms.

Reviewed by: Mary D. Daley, MD