Oxygen uptake ( [Formula: see text] O(2)) and pulmonary ventilation ( [Formula: see text] E) during military surface fin swimming in a swimming flume: Effects of surface immersion

Introduction: During military fin swimming, we suspected that oxygen uptake ( [Formula: see text] O(2)) and pulmonary ventilation ( [Formula: see text] E) might be much higher than expected. In this framework, we compared these variables in the responses of trained military divers during land cycling and snorkeling exercises. Methods: Eighteen male military divers (32.3 ± 4.2 years; 178.0 ± 5.0 cm; 76.4 ± 3.4 kg; 24.1 ± 2.1 kg m(-2)) participated in this study. They performed two test exercises on two separate days: a maximal incremental cycle test (land condition), and an incremental fin swimming (fin condition) in a motorized swimming flume. Results: The respective fin and land [Formula: see text] O(2max) were 3,701 ± 39 mL min(-1) and 4,029 ± 63 mL min(-1) (p = 0.07), these values were strongly correlated (r (2) = 0.78 p < 0.01). Differences in [Formula: see text] O(2max ) between conditions increased relative to l; [Formula: see text] O(2max) (r (2) = 0.4 p = 0.01). Fin [Formula: see text] E( max ) values were significantly lower than land [Formula: see text] E( max ) values (p = 0.01). This result was related to both the significantly lower fin Vt and f (p < 0.01 and <0.04, respectively). Consequently, the fin [Formula: see text] E( max )/ [Formula: see text] O(2max ) ratios were significantly lower than the corresponding ratios for land values (p < 0.01), and the fin and land [Formula: see text] E( max ) were not correlated. Other parameters measured at exhaustion—PaO(2), PaCO(2), and SO(2) - were similar in fin and land conditions. Furthermore, no significant differences between land and fin conditions were observed for peak values for heart rate, blood lactate concentration, and respiratory exchange ratio R. Conclusion: Surface immersion did not significantly reduce the [Formula: see text] O(2max ) in trained divers relative to land conditions. As long as [Formula: see text] O(2) remained below [Formula: see text] O(2max ), the [Formula: see text] E values were identical in the two conditions. Only at [Formula: see text] O(2max ) was [Formula: see text] E higher on land. Although reduced by immersion, [Formula: see text] E( max ) provided adequate pulmonary gas exchange during maximal fin swimming.