title: Inspiratory muscle training abolishes the blood lactate increase associated with volitional hyperpnoea superimposed on exercise and accelerates lactate and oxygen uptake kinetics at the onset of exercise.
abstract: We examined the effects of inspiratory muscle training (IMT) upon volitional hyperpnoea-mediated increases in blood lactate ([lac(-)](B)) during cycling at maximal lactate steady state (MLSS) power, and blood lactate and oxygen uptake kinetics at the onset of exercise. Twenty males formed either an IMT (n = 10) or control group (n = 10). Prior to and following a 6-week intervention, two 30 min trials were performed at MLSS (207 ± 28 W), determined using repeated 30 min constant power trials. The first was a reference trial, whereas during the second trial, from 20 to 28 min, participants mimicked the breathing pattern commensurate with 90% of the maximal incremental exercise test minute ventilation ([Formula: see text]). Prior to the intervention, the MLSS [lac(-)](B) was 3.7 ± 1.8 and 3.9 ± 1.6 mmol L(-1) in the IMT and control groups, respectively. During volitional hyperpnoea, [Formula: see text] increased from 79.9 ± 9.5 and 76.3 ± 15.4 L min(-1) at 20 min to 137.8 ± 15.2 and 135.0 ± 19.7 L min(-1) in IMT and control groups, respectively; [lac(-)](B) concurrently increased by 1.0 ± 0.6 (+27%) and 0.9 ± 0.7 mmol L(-1) (+25%), respectively (P < 0.05). Following the intervention, maximal inspiratory mouth pressure increased 19% in the IMT group only (P < 0.01). Following IMT only, the increase in [lac(-)](B) during volitional hyperpnoea was abolished (P < 0.05). In addition, the blood lactate (-28%) and phase II oxygen uptake (-31%) kinetics time constants at the onset of exercise and the MLSS [lac(-)](B) (-15%) were reduced (P < 0.05). We attribute these changes to an IMT-mediated increase in the oxidative and/or lactate transport capacity of the inspiratory muscles.
authors.affiliation: Department of Sport and Exercise, University of Derby, Kedleston Road, Derby, DE22 1GB, UK. P.Brown@derby.ac.uk
authors.forename: Peter I
authors.initials: PI
authors.lastname: Brown
authors.forename: Graham R
authors.initials: GR
authors.lastname: Sharpe
authors.forename: Michael A
authors.initials: MA
authors.lastname: Johnson
mesh_terms: D000328:Adult; D001158:Arteries / Q000502:physiology; D001945:Breathing Exercises; D004493:Education / Q000379:methods; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006985:Hyperventilation / Q000097:blood* / Q000503:physiopathology; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D012132:Respiratory Muscles / Q000378:metabolism / Q000502:physiology*
chemical_list: D019344:Lactic Acid