Effect of physical fitness on myocardial damage and circulation after myocardial necrosis.

The effect of physical training (conditioning) on myocardial circulation and myocardial damage has been evaluated in experimental myocardial necrosis in albino rats. Conditioning was done by making the animals swim in a tank of water, thermostatically controlled at 32 degrees +/- 1 degrees C, 60 minutes daily, six days a week, for eight weeks. Myocardial necrosis was produced by subcutaneous injection of isoproterenol, 85 mg/kg body weight, on two consecutive days. Investigations included ECG (lead II), SGOT, SGPT, SLDH, SCPK, histopathology of the heart, and myocardial Rubidium 84 uptake. It was observed that, in conditioned animals, elevation of serum enzymes was less, incidence of cardiac arrhythmia was lower, myocardial damage was less marked, and myocardial circulation was better after myocardial necrosis in comparison to unconditioned animals. Less myocardial damage and lower incidence of cardiac of cardiac arrhythmia are presumably associated with a better prognosis.