Echocardiographic and physiological performance characteristics of triathletes

BACKGROUND: Endurance sports require a variety of physiological adaptations . OBJECTIVE: To examine the structural and functional heart adaptations and t heir hemodynamic implications in triathletes. PATIENTS AND METHODS: A group of 52 male triathletes was compared with a co ntrol group of 22 healthy male nonathletes. All of the subjects were given a bidimensional cardiac Doppler echocardiography examination and administer ed maximal exercise tests with lactic acid determinations, on a bicycle erg ometer and a treadmill. RESULTS: The triathletes showed clear structural and functional heart adapt ations with concentric and eccentric hypertrophy with evidence of a superno rmal diastolic left ventricular function. The performance capacity of the t riathlete differed significantly from that of the control subject. The maxi mal oxygen consumption and the maximal oxygen consumption per kilogram on t he bicycle and on the treadmill were significantly higher in the triathlete s. The same results and conclusions were obtained concerning aerobic capaci ties and power outputs on a bicycle ergometer at blood lactate concentratio ns of 2, 3 and 4 mmol/L. The heart rate 6 min alter the start of exercise i s a significant parameter for the evaluation of the physical condition of a subject. The lactic acid determinations during the recovery phase enabled important conclusions to be drawn about the physical condition of the subje cts. CONCLUSIONS: The triathletes showed evidence of important structural and fu nctional heart adaptations with hemodynamic implications. The maximal perfo rming capacities, on the bicycle as well as on the treadmill, were distinct ly higher in the triathlete group. Furthermore, the aerobic and anaerobic c apacities were significantly different between the groups. In this context, the heart rate 6 min after the start of exercise and the blood lactate con centrations 20 min alter the maximal exercise test were significant paramet ers. It was not always the best triathletes who had the most significant st ructural cardiac adaptations. Thus, the 'athletic heart' syndrome as a phys iological entity is questioned.