Inspiratory Loading Intensity Does Not Influence Lactate Clearance during Recovery

• Autores: Michael a. Johnson, Dean E. Mills, David Brown, Katie J. Bayfield, Javier T. González
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 44, Nº. 5, 2012, págs. 863-871
• Idioma: inglés
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• Resumen

  • Purpose: This study examined the effects of different pressure threshold inspiratory loads on lactate clearance and plasma acid�base balance during recovery from maximal exercise.

    Methods: Eight moderately trained males (V?O2peak = 4.29 ± 0.46 L·min-1) performed, on different days, four maximal incremental cycling tests (power started at 0 W and increased by 20 W·min-1) of identical duration (exercise time during the first trial was 16.32 ± 1.12 min). During 20-min recovery, subjects either rested passively or breathed through a constant pressure threshold inspiratory load of 10 (ITL10), 15 (ITL15), or 20 (ITL20) cm H2O. Plasma lactate concentration ([La-]) was measured, and acid�base balance was quantified using the physicochemical approach, which describes the dependency of [H+] on the three independent variables: strong ion difference ([Na+] + [K+] - [Cl-] + [La-]), the total concentration of weak acids, and the partial pressure of carbon dioxide.

    Results: Peak exercise responses were not significantly different between trials. During recovery, the area under the plasma [La-] curve was not different between trials (pooled mean = 261 ± 60 mEq) and the [La-] measured at the end of the 20-min recovery was also similar (passive recovery = 9.2 ± 3.1 mEq·L-1, ITL10 = 9.3 ± 3.1 mEq·L-1, ITL15 = 8.7 ± 2.8 mEq·L-1, ITL20 = 8.7 ± 3.2 mEq·L-1). Similarly, changes in other strong ions contributing to strong ion difference and total concentration of weak acids, partial pressure of carbon dioxide, and, therefore, [H+] were not different between trials.

    Conclusions: These data suggest that, in individuals of moderate endurance training status, inspiratory loading at the intensities used in the present study does not accelerate lactate clearance or modify plasma acid�base balance during recovery from maximal exercise