Red cell oxygen transport before and after short-term maximal swimming in dependence on training status

Parameters of oxygen transport were determined in 12 national class swimmers of both sexes during a 6-week training phase. Training intensity was high at the beginning of the training period (60 km/week); at the end the intensity was reduced to 25 km/week. At the beginning, in the middle, and at the end of the training period maximal swim tests (3 X 50 m) were performed. At rest 2,3-diphosphoglycerate (2,3-DPG) concentration (+0.82 mmol/l RBC) and P50 values (+0.92 mmHg) were increased after the period of intensive training, but decreased during the following 3 weeks, remaining still higher than pre-training values. Hemoglobin (Hb), concentration (MCHC) decreased during the training phase in dependence on training intensity. On day 0 and day 25 no changes in 2,3-DPG were found during the swim tests, but at the end a significant reduction in red cell 2,3-DPG (-0.44 mmol/l RBC) occurred. This can be explained by the more pronounced lactacidosis in this last swim test. The degree of hemoconcentration during exercise was the same throughout the training period and consequently independent of the state of physical fitness. During the training period, a good correlation between training intensity, increase in red cell 2,3-DPG, and P50 value as well as in the degree of sports anemia could be found.