The condition you are describing is what is called exercise intolerance ,it is a condition where the patient is unable to do physical exercise at the level or for the duration that would be expected of someone in his or her general physical condition, or experiences unusually severe post-exercise pain, fatigue, nausea, vomiting or other negative effects. Exercise intolerance is not a disease or syndrome in and of itself, but a symptom.
Exercise intolerance is a is a common symptom among those who suffer from heart disease, mitochondrial disease or metabolic disorders. In such cases, the normal conversion of food or oxygen into energy is disrupted, leaving the patient without an adequate supply. Degrees of exercise intolerance can vary: it can exhibit itself after the mildest exertions or require more sustained effort to be recognized. Likewise, it can afflict the sufferer during exercise or later.
For even the physically fit, vigorous exercise taxes the organs and muscles of the respiratory system. When exhaustion is reached, continued effort can lead to shortness of breath and dizziness. These sensations signal that oxygen no longer is being processed efficiently and rest is required. In the case of an exercise intolerant individual, the exhaustion threshold may show within minutes of starting physical activity. Worse, fatigue can be induced by seemingly innocuous activity such as eating or writing.
> Heart problems are one major cause of exercise intolerance, since certain cardiac issues can reduce the availability of oxygenated blood to the various muscles of the body.
>Metabolic muscle diseases can also cause an intolerance to exercise, since these conditions can result in individual muscles not having enough energy.
>Other conditions that can cause similar symptoms include anemia, chronic fatigue
syndrome, and back pain, which can make it difficult to maintain exercise levels.
YOUR FRIEND MUST CHECK WITH A DOCTOR FOR a check up full examination ,blood tests and exercise electrocardiogram (ECG),An exercise tolerance test (ETT)ECG tracings are made and you will also have your blood pressure measured from time to time. The test lasts about 15-20 minutes.
The cause must be known to deal with condition and take the necessary treatment and exercise plan .