Dysfunctions involving the pulmonary, cardiovascular or neuromuscular systems have been frequently found to be associated with exercise intolerance, with behavioural causes also playing a part.

For example, a person with exercise intolerance after a heart attack may not be able to sustain the amount of physical activity needed to walk through a grocery store or to cook a meal.

[citation needed] The three most common reasons people give for being unable to tolerate a normal amount of exercise or physical activity are: Metabolic myopathies are inherited inborn errors of metabolism that affect the ability of the muscle to produce ATP, either aerobically (cellular respiration) or anaerobically (glycolysis and lactic acid fermentation).

[citation needed] Individuals with elevated levels of cerebrospinal fluid can experience increased head pain, throbbing, pulsatile tinnitus, nausea and vomiting, faintness and weakness and even loss of consciousness after exercise or exertion.

[citation needed] A person who is not physically fit due to a sedentary lifestyle may find that vigorous exercise is unpleasant.

[27] Research on individuals with Chronic obstructive pulmonary disease (COPD), has found a number of effective therapies in relation to exercise intolerance.

[28] Certain conditions exist where exercise may be contraindicated or should be performed under the direction of an experienced and licensed medical professional acting within his or her scope of practice.