The effects of pressure-threshold inspiratory load on lactate clearance after maximal exercise

The effects of pressure-threshold inspiratory load on lactate clearance after maximal exercise

Chiappa, G.R. et al. (Med Sci Sports Exerc 2008; 40:111-116) showed that a 15 cmH2O pressure-threshold inspiratory load accelerated lactate clearance during recovery from intense exercise. However, we observed such an effect only when the relative intensity of the inspiratory load fell due to a training-induced increase in maximum inspiratory pressure (Brown, P.I. et al. Med Sci Sports Exerc 2010;
42:1103-1112). This study thus tested the hypothesis that lactate clearance is influenced by the magnitude of inspiratory load applied in recovery from maximal
exercise.

Eight male participants (VO2max 4.34±0.54 L/min) completed four maximal incremental cycling tests (20 W/min starting at 0W), of identical duration (16.20±1.22 min), followed by 20 min recovery comprising either passive recovery (PR) or
breathing against an inspiratory pressure-threshold load of either 10 (IPTL10), 15 (IPTL15) or 20 (IPTL20) cmH2O. Arterialised venous blood samples were taken during recovery and analysed for blood lactate concentration ([La]B) every 2 min and blood pH every 4 min. During PR, IPTL10, IPTL15 and IPTL20 the [La]B after 2 min of recovery (11.2±1.9, 11.5±2.6, 11.2±2.0 and 11.2±1.8 mmol/L, respectively), the area under the [La]B curve during recovery (191±48, 192±55, 182±48 and 187±45 mmol, respectively), and mean blood pH (7.27±0.05, 7.28±0.05,
7.28±0.06 and 7.28±0.06, respectively) were not different between trials.

In conclusion, all inspiratory loads failed to influence lactate clearance after maximal exercise. Why inspiratory loading accelerates lactate clearance in some
(Chiappa et al.), but not all (present study; Brown et al.), participants is thus unclear and warrants further exploration.

Poster presentation. Abstract only published.