[Cardiac exercise tolerance of infarct patients in exercise therapy]

92 female patients with myocardial infarction were divided into three exercise groups of 25 W, 50 W and 75 W according to their symptom-limited working capacity and examined during bicycle ergometer training. Exercise tolerance, training heart rate and arterial lactic acid were analyzed.

1. Increase in maximal working capacity corresponds to a decrease in limiting cardiac symptoms, or an increase of limiting symptoms, e.g., in tired leg muscles. 2. Intensity of training (as a percentage of maximal symptom-limited work capacity) is 55 +/- 21%, 73 +/- 15%, and 90 +/- 8% for groups of 25, 50 and 75 W (p less than 0.05) respectively. 3. Training heart rate and lactic acid increase significantly proportional to the increase of work capacity. 4. In all three exercise groups, training heart rate corresponds to about 84% maximal heart rate measured at maximal working capacity. 5. Mean maximal lactic acid level is at 3.18 +/- 0.97 mmol/l for the whole exercise group on 75 W. Within this group, only a small subgroup of seven women, who were limited in maximal working capacity by tired leg muscles, reached the so-called anaerobic threshold of 4 mmol/l lactic acid. 6. Female patients greater than or equal to 60 years have partially significant higher mean lactic acid levels for the same exercise load as women less than or equal to 59 years.

Gender specific differences in performance in women and the cardiac situation in female patients were considered on the basis of symptom-limited performance and body-weight-related physical training, regulated by individual training heart rate.