title: Salbutamol effects on systemic potassium dynamics during and following intense continuous and intermittent exercise.
abstract: OBJECTIVE
  Salbutamol inhalation is permissible by WADA in athletic competition for asthma management and affects potassium regulation, which is vital for muscle function. Salbutamol effects on arterial potassium concentration ([K+]a) during and after high-intensity continuous exercise (HIcont) and intermittent exercise comprising repeated, brief sprints (HIint), and on performance during HIintare unknown and were investigated.
  
  
  METHODS
  Seven recreationally active men participated in a double-blind, randomised, cross-over design, inhaling 1000 µg salbutamol or placebo. Participants cycled continuously for 5 min at 40 % [Formula: see text]O2peakand 60 % [Formula: see text]O2peak, then HIcont(90 s at 130 % [Formula: see text]O2peak), 20 min recovery, and then HIint(3 sets, 5 × 4 s sprints), with 30 min recovery.
  
  
  RESULTS
  Plasma [K+]aincreased throughout exercise and subsequently declined below baseline (P < 0.001). Plasma [K+]awas greater during HIcontthan HIint(P < 0.001, HIcont5.94 ± 0.65 vs HIintset 1, 4.71 ± 0.40 mM); the change in [K+]afrom baseline (Δ[K+]a) was 2.6-fold greater during HIcontthan HIint(P < 0.001). The Δ[K+] throughout the trial was less with salbutamol than placebo (P < 0.001, treatment main effect, 0.03 ± 0.67 vs 0.22 ± 0.69 mM, respectively); and remained less after correction for fluid shifts (P < 0.001). The Δ[K+] during HIcontwas less after salbutamol (P < 0.05), but not during HIint. Blood lactate, plasma pH, and the work output during HIintdid not differ between trials.
  
  
  CONCLUSIONS
  Inhaled salbutamol modulated the [K+]arise across the trial, comprising intense continuous and intermittent exercise and recovery, lowering Δ[K+] during HIcont. The limited [K+]achanges during HIintsuggest that salbutamol is unlikely to influence systemic [K+] during periods of intense effort in intermittent sports.
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
authors: Muath M
authors: MM
authors: Altarawneh
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
authors: Aaron
authors: A
authors: Petersen
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.|Department of Anaesthesia, Western Hospital, Melbourne, Australia.
authors: Robert
authors: R
authors: Smith
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
authors: David M
authors: DM
authors: Rouffet
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.|Département de Kinésiologie, Université Laval, Québec, Canada.
authors: Francois
authors: F
authors: Billaut
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
authors: Ben D
authors: BD
authors: Perry
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
authors: Victoria L
authors: VL
authors: Wyckelsma
authors: Intensive Care Unit, St Vincent's Hospital, Melbourne, Australia.
authors: Antony
authors: A
authors: Tobin
authors: Institute of Sport, Exercise and Active Living (ISEAL), Clinical Exercise Science Research Program, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia. michael.mckenna@vu.edu.au.
authors: Michael J
authors: MJ
authors: McKenna
mesh_terms: D000280:Administration, Inhalation; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D000072696:High-Intensity Interval Training / Q000379:methods*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000097:blood*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol; D011188:Potassium
keywords: Fatigue; Hypokalemia; K+; K+-ATPase; Na+; Repeat sprint exercise; β2-Adrenergic agonist