title: Pseudoephedrine and circadian rhythm interaction on neuromuscular performance.
abstract: This study analyzed the effects of pseudoephedrine (PSE) provided at different time of day on neuromuscular performance, side effects, and violation of the current doping cut-off threshold [World Anti-Doping Agency (WADA)]. Nine resistance-trained males carried out bench press and full squat exercises against four incremental loads (25%, 50%, 75%, and 90% one repetition maximum [1RM]), in a randomized, double-blind, cross-over design. Participants ingested either 180 mg of PSE (supra-therapeutic dose) or placebo in the morning (7:00 h; AM(PLAC) and AM(PSE)) and in the afternoon (17:00 h; PM(PLAC) and PM(PSE)). PSE enhanced muscle contraction velocity against 25% and 50% 1RM loads, only when it was ingested in the mornings, and only in the full squat exercise (4.4-8.7%; P < 0.05). PSE ingestion raised urine and plasma PSE concentrations (P < 0.05) regardless of time of day; however, cathine only increased in the urine samples. PSE ingestion resulted in positive tests occurring in 11% of samples, and it rose some adverse side effects such us tachycardia and heart palpitations. Ingestion of a single dose of 180 mg of PSE results in enhanced lower body muscle contraction velocity against low and moderate loads only in the mornings. These mild performance improvements are accompanied by undesirable side effects and an 11% risk of surpassing the doping threshold.
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.|Genoarchitecture Group, University of Murcia, Murcia, Spain.
authors.forename: J G
authors.initials: JG
authors.lastname: Pallarés
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: Á
authors.initials: Á
authors.lastname: López-Samanes
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: V E
authors.initials: VE
authors.lastname: Fernández-Elías
authors.affiliation: Department of Health Sciences, Public University of Navarra, Pamplona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Aguado-Jiménez
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: J F
authors.initials: JF
authors.lastname: Ortega
authors.affiliation: Bioanalysis and Analytical Services Research Group Neurosciences Program, IMIM, Hospital del Mar Medical Research Institute, Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Gómez
authors.affiliation: Bioanalysis and Analytical Services Research Group Neurosciences Program, IMIM, Hospital del Mar Medical Research Institute, Barcelona, Spain.|Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Ventura
authors.affiliation: Bioanalysis and Analytical Services Research Group Neurosciences Program, IMIM, Hospital del Mar Medical Research Institute, Barcelona, Spain.|Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Segura
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Mora-Rodríguez
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D018592:Cross-Over Studies; D004300:Doping in Sports; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D014663:Nasal Decongestants / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism; D010665:Phenylpropanolamine / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism; D054199:Pseudoephedrine / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism; D055070:Resistance Training; D013610:Tachycardia / Q000139:chemically induced; D055815:Young Adult
chemical_list: D014663:Nasal Decongestants; C005331:norpseudoephedrine; D010665:Phenylpropanolamine; D054199:Pseudoephedrine
keywords: Chronobiology; adrenergic agents; central nervous system stimulant; doping; ergogenic aid; muscle strength