Five-year follow-up of ECG aberrations, latent coronary heart disease and cardiopulmonary fitness in various age groups of Norwegian cross-country skiers.

A cross-sectional sample of 122 middle-aged and elderly long-time active, well-trained male cross-country skiers were studied in 1976 to assess the prevalence of possible latent coronary heart disease (CHD). One hundred and seventeen skiers were reexamined five years later to assess the prognostic significance of a number of ECG aberrations encountered in 1976, and to assess the CHD incidence among athletes. One had died and four did not participate in the restudy, but none of these five men had had cardiac disease. The findings at the time of the two surveys were remarkably similar. All had excellent physical performance and a stable life habit pattern. Only three had given up regular training in the observation period. There was a very high prevalence of sinus bradycardia, first degree AV blocks, left ventricular hypertrophy (LVH) and incomplete right bundle branch block. Pathologic exercise ECGs were found on both occasions. Of 23 men with "pathologic" exercise ECG, 21 had LVH. Five had codable Q waves according to the Minnesota code, but none had symptoms of CHD. Two developed angina pectoris during the follow-up and none had had myocardial infarction. It is concluded that the large number of ECG aberrations found in middle-aged and elderly athletes are mainly related to physiological adaptation to training and that training seems to protect against CHD.