The significance of positive ST-T changes during bathing, eating, defecating and urinating was studied in 103 patients with ischemic heart disease using Holter and 12-lead ECG. The incidence of positive ST-T changes was very high in patients with unstable angina (US) and in those with old myocardial infarction (OMI) associated with unstable angina. However, it was relatively low in angina-free OMI and extremely low in stable angina. Positive ST-T changes during defecation and urination were mostly (70% and 73%, respectively) seen from night to early morning. With regard to showering or eating, the incidence of positive ST-T changes was low during spraying hot water on the body without motion or remaining motionless after eating. It was not until light exertion was added that the incidence increased. However, pressure-rate product after such behavior did not always increase as compared with that before them. Consequently, it is suggested that the mechanism of anginal attack during urination may be similar to that of variant angina. With regard to showering or eating, it is considered that the spraying of hot water or food intake may bring about a change in the cardiac autonomic nerve tone, and that the addition of light exertion can easily induce myocardial ischemia which is not due to an increase in the oxygen demand of the myocardium.