title: Effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat.
abstract: This study examined the separate effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. Participants (N = 10) performed three trials in a counterbalanced order, either with 400 mg caffeine, menthol lozenges, or placebo. The simulated firefighting consisted of 2 bouts of 20-min treadmill exercise and one bout of 20-min stepping exercise in the heat with two brief 15-min rest periods between each exercise phase. Exercise induced significant dehydration (>3%) and elevated rectal temperature (>38.9 °C), for all three conditions. Neither caffeine nor menthol reduced perceived exertion compared to placebo (p > 0.05). Mood ratings (i.e., alertness, hedonic tone, tension) significantly deteriorated over time (p < 0.05), but there was no difference among the three conditions. Simple reaction time, short-term memory, and retrieval memory did not alter with treatments or repeated evaluations. Reaction accuracy from a math test remained unchanged throughout the experimental period; reaction time from the math test was significantly faster after exposure to the heat (p < 0.05). It is concluded that, exhaustive exercise in the heat severely impacted mood, but minimally impacted cognition. These treatments failed to show ergogenic benefits in a simulated firefighting paradigm in a hot environment.
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA. Electronic address: yzhang68@bama.ua.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Gytis
authors.initials: G
authors.lastname: Balilionis
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Catalina
authors.initials: C
authors.lastname: Casaru
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Colleen
authors.initials: C
authors.lastname: Geary
authors.affiliation: Department of Educational Studies in Psychology, Research Methodology, and Counseling, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Randall E
authors.initials: RE
authors.lastname: Schumacker
authors.affiliation: Department of Human Nutrition, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Yasmin H
authors.initials: YH
authors.lastname: Neggers
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Curtner-Smith
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Richardson
authors.affiliation: Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Bishop
authors.affiliation: Department of Health, Physical Education, and Recreation, University of North Alabama, Florence, AL 35632, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Green
mesh_terms: D000339:Affect / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D061388:Firefighters / Q000523:psychology*; D005390:Fires; D006339:Heart Rate / Q000187:drug effects; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male; D008610:Menthol / Q000494:pharmacology*; D009483:Neuropsychological Tests; D005082:Physical Exertion / Q000187:drug effects; D015431:Weight Loss / Q000187:drug effects; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D008610:Menthol; D002110:Caffeine
keywords: Cognitive performance; Dehydration; Hyperthermia; Protective clothing