Inspiratory loading intensity does not influence lactate clearance during recovery

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Johnson, M.A. ORCID: 0000-0002-8226-9438, Mills, D.E., Brown, D.M., Bayfield, K.J., Gonzalez, J.T. and Sharpe, G.R. ORCID: 0000-0002-4575-2332, 2012. Inspiratory loading intensity does not influence lactate clearance during recovery. Medicine & Science in Sports & Exercise, 44 (5), pp. 863-871. ISSN 0195-9131

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Official URL: http://dx.doi.org/10.1249/MSS.0b013e31824079d0

Abstract

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˙O2 peak = 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) cmH2O. 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 ([SID] = [Na+] + [K+] – [Cl-] + [La-]), the total concentration of weak acids ([Atot-]), and the partial pressure of carbon dioxide (PCO2).

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 [SID], and [Atot-], PCO2, and therefore [H+], were not different between trials.

Conclusion: 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.

Item Type:

Journal article

Publication Title:

Medicine & Science in Sports & Exercise

Creators:

Johnson, M.A., Mills, D.E., Brown, D.M., Bayfield, K.J., Gonzalez, J.T. and Sharpe, G.R.

Publisher:

Lippincott Williams & Wilkins for the American College of Sports Medicine

Place of Publication:

Indianapolis, IN

Date:

2012