Enhanced pulmonary and active skeletal muscle gas exchange during intense exercise after sprint training in men

1. This study investigated the effects of 7 weeks of sprint training on gas exchange across the lungs and active skeletal muscle during and following maximal cycling exercise in eight healthy males. 2. Pulmonary oxygen uptake (V-o2) and carbon dioxide output (V-co2) mere measured before and after training during incremental exercise (n=8) and during and in recovery from a maximal 30 s sprint exercise bout by breath-by-breath analysis (n=6). To determine gas exchange by the exercising leg muscles, brachial arterial and femoral venous blood O-2 and CO2 contents and lactate concentration were measured at rest, during the final 10 s of exercise and during 10 min of recovery. 3. Training increased (P<0.05) the maximal incremental exercise values of ventilation (V-E, by 15.7+/-7.1%), V-co2 (by 9.3+/-2/1%) and Vo(2) (by 15.0+/-4.2%). Sprint exercise peak power (3.9+/-1.0% increase) and cumulative 30 s work (11.7+/-2.8% increase) were increased and fatigue index was reduced (by -9.2+/-1.5%) after training (P<0.05). The highest V-E, V-co2 and V-o2 values attained during sprint exercise were not significantly changed after training, but a significant (P<0.05) training effect indicated increased V-E (by 19.2+/-7.9%), V-co2 (by 9.3+/-2.1%) and V-o2 (by 12.7+/-6.5%), primarily reflecting elevated post-exercise values after training. 4. Arterial O-2 and CO2 contents were lower after training, by respective mean differences of 3.4 and 21.9 mll(-1) (P<0.05), whereas the arteriovenous O-2 and CO2 content differences and the respiratory exchange ratio across the leg were unchanged by training. 5. Arterial whole blood lactate concentration and the net lactate release by exercising muscle were unchanged by training. 6. The greater peak pulmonary V-o2 and V-co2 with sprint exercise, the increased maximal incremental values, unchanged arterial blood lactate concentration and greater sprint performance all point strongly towards enhanced gas exchange across the lungs and in active muscles after sprint training. Enhanced aerobic metabolism after sprint training may contribute to reduced fatigability during maximal exercise, whilst greater pulmonary CO2 output may improve acid-base control after training.