Combined caffeine and ephedrine ingestion improves run times of Canadian Forces Warrior Test.
The ingestion of a combination of caffeine (C) and ephedrine (E) has been reported to prolong exercise time to exhaustion during cycle ergometry at 85% VO2max. The present study was undertaken to investigate whether this enhancement would occur in a field setting and if drug ingestion on 1 d would affect performance 1 d later. Two hours after ingesting either a combination of 375 mg of C and 75 mg E (C+E), or a placebo (P), 9 healthy male recreational runners completed six balanced and double-blind trials of the Canadian Forces Warrior Test (WT), a 3.2 km run wearing "fighting order" which weighed about 11 kg. The trials were performed in sets of two runs, i.e., two runs were done 24 h apart, and these sets were separated by a minimum of 7 d. The sets were: C+E trial on day 1 (D1), placebo on day 2 (P2); placebo first (P1), C+E second (D2); and placebo first (P3), placebo second (P4). In addition, 1 wk before the treatment trials the subjects performed a control trial WT. During the WT, heart rates (HR) were recorded every minute. Plasma C and E levels immediately before the WT were similar for both C+E trials, but were undetectable for all P trials. Run times (mean+/-SD) were 15.3+/-0.6, 15.4+/-0.9, 15.5+/-1.2, 15.4+/-0.9, 15.4+/-0.9, 14.8+/-0.7, and 14.6+/-0.8 min for control, P1, P2, P3, P4, D1, D2 trials, respectively. The two C+E trial run times were similar and both were significantly faster (p < 0.05) than control and all placebo trials. HR during the WT was significantly higher (p < 0.05) for the C+E trials compared with the other trials. WT performance was not impaired by C+E ingestion 24 h earlier. In conclusion, performance of the WT was improved by ingestion of C+E.
Bell
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DG
Defence and Civil Institute of Environmental Medicine, Toronto, Ontario, Canada.
Jacobs
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D000328:Adult; D000704:Analysis of Variance; D002110:Caffeine / Q000097:blood / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000097:blood / Q000494:pharmacology*; D016903:Drug Monitoring; D004359:Drug Therapy, Combination; D004734:Energy Metabolism / Q000187:drug effects; D004809:Ephedrine / Q000097:blood / Q000494:pharmacology*; D005080:Exercise Test; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008889:Military Personnel; D010807:Physical Endurance / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects*; D012420:Running; D013997:Time Factors; D016474:Weight-Bearing
D000697:Central Nervous System Stimulants; D002110:Caffeine; D004809:Ephedrine