Abstract
Medical examinations and recording of electrocardiograms at rest and during exercise on the bicycle ergometer were carried out in 422 forest workers aged 25–34 and 45–54. In 39 out of 102 persons in whom segmental ST changes were recorded in connection with exercise, cardiovascular conditions were diagnosed, compared with 29 out of the other 332 performing the exercise test. The difference is significant (p < 0.001). The exercise was continued up to a previously specified heart rate, varying with age, and the electrocardiograms were analysed in accordance with the modified Minnesota code (5).