Oxygen uptake (Formula presented.) and pulmonary ventilation (Formula presented.) during military surface fin swimming in a swimming flume: Effects of surface immersion

Abstract

Introduction: During military fin swimming, we suspected that oxygen uptake ((Formula presented.) O2) and pulmonary ventilation ((Formula presented.) 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 presented.) O2max were 3,701 ± 39 mL min-1 and 4,029 ± 63 mL min-1 (p = 0.07), these values were strongly correlated (r2 = 0.78 p < 0.01). Differences in (Formula presented.) O2max between conditions increased relative to l; (Formula presented.) O2max (r2 = 0.4 p = 0.01). Fin (Formula presented.) Emax values were significantly lower than land (Formula presented.) Emax 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 presented.) Emax/ (Formula presented.) O2max ratios were significantly lower than the corresponding ratios for land values (p < 0.01), and the fin and land (Formula presented.) Emax were not correlated. Other parameters measured at exhaustion—PaO2, PaCO2, and SO2 - 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 presented.) O2max in trained divers relative to land conditions. As long as (Formula presented.) O2 remained below (Formula presented.) O2max, the (Formula presented.) E values were identical in the two conditions. Only at (Formula presented.) O2max was (Formula presented.) E higher on land. Although reduced by immersion, (Formula presented.) Emax provided adequate pulmonary gas exchange during maximal fin swimming.