Long-term effect of previous swimtraining in girls. A 10-year follow-up of the "girl swimmers".
Thirty girls, studied in 1961 after 2.5 years of intensive swimtraining, were the subject of a follow-up for ten years. When last examined, seven and ten years after the original study, all the girls had given up swimtraining. The increased values for vital capacity observed in 1961 remained unchanged, but residual volume, functional residual capacity and total lung capacity showed small increases even after corrections for body growth. Such increases are, however, normal in these years. Heart volume which was high originally, was found to be lower ten years later, although mean values were still higher than normal. The decreases seen from 1961 to 1971 could mainly be ascirbed to a decrease in the subjects with the larges hearts originally. Both total hemoglobin and blood volume decreased to normal values in relation to body size. Maximal oxygen uptake, though, fell from 2.80 l/min (51. 4 ml/kg X min) to 2.18 l/min (36.4 ml/kg X min) ten years later. It is suggested that the functional capacity of the cardiovascular system declined more markedly than its dimensions.