Research article - (2017)16, 581 - 588
The Effect of 400 µg Inhaled Salbutamol on 3 km Time Trial Performance in a Low Humidity Environment
John Molphy1,2,, John W. Dickinson1, Neil J. Chester2, Mike Loosemore3, Gregory Whyte2
1Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Chatham Maritime, UK
2Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
3Institute of Sport Exercise and Health, University College London, London, UK

John Molphy
✉ University of Kent, Medway Campus, Chatham Maritime, Kent ME4 4AG, UK
Email: j.r.molphy@kent.ac.uk
Received: 13-09-2017 -- Accepted: 01-11-2017
Published (online): 01-12-2017
ABSTRACT

The Objectives of the study were to investigate whether 400 µg inhaled salbutamol influences 3 km running time-trial performance and lung function in eucapnic voluntary hyperpnoea positive (EVH+ve) and negative (EVH-ve) individuals. Fourteen male participants (22.4 ± 1.6yrs; 76.4 ± 8.7kg; 1.80 ± 0.07 m); (7 EVH+ve; 7 EVH-ve) were recruited following written informed consent. All participants undertook an EVH challenge to identify either EVH+ve (↓FEV1>10%) or EVH-ve (↓FEV1<10%). Participants performed three separate 3 km running time-trials in a low-humidity (20-25%) environment on a non-motorized treadmill, 15 minutes following inhalation of salbutamol (400 µg), placebo (non-active inhalant) or control (no inhalant), in a randomized, single-blind, repeated measures design. Forced vital capacity maneuvers were performed at baseline, 10 minutes post inhalation and post time-trial. Time to complete 3 km and lung function data were analyzed using mixed model repeated measures ANOVA. Significance was assumed at p < 0.05. All EVH+ve participants had FEV1 falls from baseline between 10-25% post-challenge. There was no difference in performance time between trial conditions in EVH+ve (1012.7 ± 129.6s; 1002.4 ± 123.1s; 1015.9 ± 113.0s) (p = 0.774) and EVH-ve (962.1 ± 99.2s; 962.0 ± 76.2s; 950.8 ± 84.9s) (p = 0.401) groups for salbutamol, placebo and control trials, respectively. Exercising heart rate was significantly higher (p = 0.05) in the salbutamol trial (183 ± 8 beatsË‘min-1) compared to control (180 ± 9 beatsË‘min-1) with a trend towards significance (p=0.06) in the placebo trial (179 ± 9 beatsË‘min-1) for the pooled groups, no differences were seen between trials in groups individually. There was an increase in FEV1 in both EVH+ve (4.01 ± 0.8L; 4.26 ± 0.7L; 4.25 ± 0.5L) and EVH-ve (4.81 ± 0.4L; 5.1 ± 0.4L; 5.1 ± 0.5L) groups which was significant post-inhalation (p = 0.01; p = 0.02), but not post-time-trial (p = 0.27; p = 0.06), respectively, following salbutamol. EVH+ve participants did not demonstrate significant falls (>10% from baseline) in FEV1 following any time-trial. Administration of 400µg inhaled salbutamol does not improve 3 km time-trial performance in either mild EVH+ve or EVH–ve individuals despite significantly increased HR and FEV1.
Key words: Asthma, exercise, bronchoconstriction, ergogenic, bronchoprovocation

Key Points
  • Athletes with EIB require short-acting β2-agonists for the relief and/or prevention of symptoms during sporting performance which has the potential to be ergogenic.
  • The present study demonstrates that there is no ergogenic effect from their therapeutic use in healthy active individuals during 3 km running time-trial performance.
  • Athletes with mild EIB may exhibit airway hyper-responsiveness in bronchoprovocative environments.
  • The present study demonstrates that individuals with a mild positive response to EVH challenge do not exhibit with EIB during intense exercise in a low humidity (20-25%) environment.








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The Effect of 400 µg Inhaled Salbutamol on 3 km Time Trial Performance in a Low Humidity Environment
John Molphy, John W. Dickinson, Neil J. Chester, Mike Loosemore, Gregory Whyte
2017(16), 581 - 588.
DOI: https://doi.org/