title: Caffeine lowers perceptual response and increases power output during high-intensity cycling.
abstract: The aim of this study was to determine the effects of caffeine ingestion on a 'preloaded' protocol that involved cycling for 2 min at a constant rate of 100% maximal power output immediately followed by a 1-min 'all-out' effort. Eleven male cyclists completed a ramp test to measure maximal power output. On two other occasions, the participants ingested caffeine (5 mg. kg(-1)) or placebo in a randomized, double-blind procedure. All tests were conducted on the participants' own bicycles using a Kingcycle test rig. Ratings of perceived exertion (RPE; 6-20 Borg scale) were lower in the caffeine trial by approximately 1 RPE point at 30, 60 and 120 s during the constant rate phase of the preloaded test (P <0.05). The mean power output during the all-out effort was increased following caffeine ingestion compared with placebo (794+/-164 vs 750+/-163 W; P=0.05). Blood lactate concentration 4, 5 and 6 min after exercise was also significantly higher by approximately 1 mmol. l(-1) in the caffeine trial (P <0.05). These results suggest that high-intensity cycling performance can be increased following moderate caffeine ingestion and that this improvement may be related to a reduction in RPE and an elevation in blood lactate concentration.
authors.affiliation: Department of Sport, Exercise and Biomedical Sciences, University of Luton, Luton LU1 3JU. mike.doherty@luton.ac.uk
authors.forename: Mike
authors.initials: M
authors.lastname: Doherty
authors.forename: Paul
authors.initials: P
authors.lastname: Smith
authors.forename: Michael
authors.initials: M
authors.lastname: Hughes
authors.forename: Richard
authors.initials: R
authors.lastname: Davison
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002110:Caffeine / Q000494:pharmacology*; D005080:Exercise Test; D005221:Fatigue; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D010465:Perception / Q000187:drug effects / Q000502:physiology; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects* / Q000502:physiology; D010919:Placebos; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
chemical_list: D007773:Lactates; D010919:Placebos; D002110:Caffeine