Acute Effects of Albuterol on Ventilatory Capacity in Children with Asthma.

BACKGROUND: Children with asthma may have a reduced ventilatory capacity, which could lead to symptoms and early termination of a cardiopulmonary exercise test (CPET). The purpose of this study was to examine the effects of short-acting beta agonist (albuterol) administration on estimated ventilatory capacity in children with asthma. METHODS: Fifteen children (eleven boys, 10.6 ± 0.9 years) completed spirometry at baseline, after 180 µg of albuterol, and after the CPET in this cross-sectional study. Ventilatory capacity was calculated from forced vital capacity (FVC) and isovolume forced expiratory time from 25 to 75% of FVC (isoFET25-75) as follows: FVC/2 × [60/(2 × isoFET25-75)]. Differences in outcome variables between baseline, after albuterol administration, and after the CPET were detected with repeated measures mixed models with Bonferroni post hoc corrections. RESULTS: Estimated ventilatory capacity was higher after albuterol (68.7 ± 21.2 L/min) and after the CPET (75.8 ± 25.6 L/min) when compared with baseline (60.9 ± 22.0 L/min; P = 0.003). Because forced vital capacity did not change, the increased ventilatory capacity was primarily due to a decrease in isoFET25-75 (i.e., an increase in mid-flows or isoFEF25-75). CONCLUSION: Albuterol administration could be considered prior to CPET for children with asthma with relatively well-preserved FEV1 values to increase ventilatory capacity pre-exercise and potentially avoid symptom-limited early termination of testing.

Respiratory and Perceptual Responses to High-Intensity Interval Exercise in Obese Adults.

PURPOSE: Although high-intensity interval exercise (HIIE) has emerged as an attractive alternative to continuous exercise (CE), the effects of HIIE on ventilatory constraints and dyspnea on exertion have not been studied in obese adults, and thus, tolerability of HIIE in obese adults is unknown. The purpose of this study was to examine differences in respiratory and perceptual responses between HIIE and CE in nonobese and obese adults. METHODS: Ten nonobese (5 men; 24.1 ± 6.2 yr; body mass index, 23.0 ± 1.3 kg·m-2) and 10 obese (5 men; 24.2 ± 3.8 yr; body mass index, 37 ± 4.6 kg·m-2) adults participated in this study. Respiratory and perceptual responses were assessed during HIIE (eight 30-s intervals at 80% maximal work rate, with 45-s recovery periods) and two 6-min sessions of CE, completed below and above ventilatory threshold (Vth). RESULTS: Despite similar work rate, HIIE was completed at a higher relative intensity in obese when compared with nonobese participants (68.8% ± 9.4% vs 58.9% ± 5.6% maximal oxygen uptake, respectively; P = 0.01). Expiratory flow limitation and/or dynamic hyperinflation was present during HIIE in 50% of the obese but in none of the nonobese participants. Ratings of perceived breathlessness were highest during HIIE (5.3 ± 2.4), followed by CEaboveVth (2.5 ± 1.6), and CEbelowVth (0.9 ± 0.7; P < 0.05) in obese participants. Unpleasantness associated with breathlessness was higher in obese (4.2 ± 3.0) when compared with nonobese participants (0.6 ± 1.3; P = 0.005) during HIIE. CONCLUSIONS: HIIE, when prescribed relative to maximal work rate, is associated with greater ventilatory constraints and dyspnea on exertion when compared with CE in obese adults. CE may be more tolerable when compared with HIIE for obese adults.

The Effects of a Multi-Ingredient Performance Supplement Combined with Resistance Training on Exercise Volume, Muscular Strength, and Body Composition.

The effects of a multi-ingredient performance supplement (MIPS) incorporating a mixture of branched chain amino acids, beta-alanine, glutamine, creatine, and piperine on resistance training (RT)-induced adaptations remains unclear. Therefore, the purpose of this study was to investigate the effects of this investigational MIPS during six weeks of RT on performance and body composition. Thirty recreationally trained males and females were recruited for this pair-matched, double-blind, placebo-controlled investigation. Subjects were assigned to consume either an experimental MIPS (MIPS) (n = 15) or a placebo (PLA) (n = 15) concurrently with a six-week periodized RT program. Body composition, one-repetition maximum (1RM), and muscular power were assessed at pre- and post-training. Weekly relative volume load was compared between groups. The MIPS and PLA groups demonstrated a significant increase in total body mass (MIPS = +2.9 ± 1.3%; PLA = +2.5 ± 1.7%) and lean mass (MIPS = +5.0 ± 2.1%; PLA = +3.1 ± 1.9%) (p < 0.001) with no changes in fat mass. There were no group × time interactions for any of the body composition measures. Both groups demonstrated similar improvements in maximum strength for the back squat, bench press, and deadlift as well as lower body power from pre- to post-training (p < 0.001). Within the limitations of the current investigation, results failed to demonstrate the benefits of the experimental MIPS for muscular strength and body composition across six weeks of RT compared to PLA.