The effect of different training programs on various physiological parameters and the role of a possible placebo effect was investigated in 33 patients after myocardial infarction who suffered from angina pectoris.During the first 40 weeks, all patients practiced together in a slow rate low intensity training program. Then patients were divided according to the severity of pain during stress testing and daily activities, into two groups: (1) those with severe pain (n = 18) started intensive (90% of pain threshold heart rate), prolonged (continuous 30 min) ergometric training, and (2) patients (n = 15) with lesser complaints who continued with the calisthenics program. The results of the latter group, after 18 months of training, did not reveal a significant change in submaximal heart rate (HR), systolic blood pressure (SBP), O<sub>2</sub> pulse, double or triple product (DP, TP). However, in 20% of the patients a higher pain threshold HR was tolerated and the higher DP reached before onset of anginal pain.Ergometric training caused a significant change in all the circulatory parameters mentioned above. In addition, four patients increased their pain threshold of both HR and DP. It is clear that 20% of the patients increased their maximal HR and DP, regardless of exercise intensity. The following conclusions are suggested: (1) favorable changes in physiological parameters are responsible for the improved work performance. (2) Training intensity plays the most important role in achieving the benefit of the exercise program with anginal patients. (3) Psychological response can be achieved whether or not physiological improvement is demonstrated.