Exercise tolerance is the level of physical exertion you’re able to achieve before reaching a state of exhaustion. Exercise intolerance means you’re unable to attain the level or duration of physical exercise that would be expected based on your general physical condition or level of experience.
Exercise intolerance is marked by becoming very tired easily, experiencing extreme fatigue during exercise or unusually severe pain, fatigue or other negative effects after exercising.
Exercise intolerance is not a disease, but a symptom. Exercise intolerance is often caused by some sort of health condition, like:
- COPD
- anemia
- overtraining
- heart failure
- fibromyalgia
- cor pulmonale
- hypopituitarism
- rhabdomyolysis
- McArdle’s disease
- metabolic myopathy
- mitochondrial disease
- neuromuscular disease
- chronic fatigue syndrome
- aortic stenosis & insufficiency
- dopamine beta-hydroxylase deficiency
The specific reasons why exercise could be causing intolerant fatigue symptoms is because you may be encountering dyspnea, myalgia or increasing muscle weakness during your workouts.