EFFECTS OF CAFFEINE, EPHEDRINE AND THEIR COMBINATION ON TIME TO EXHAUSTION DURING HIGH-INTENSITY EXERCISE

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Authors
  1. Bell, D.G.
  2. Jacobs, I.
  3. Zamecnik, J.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
This study investigated the effects of acute ingestion of caffeine (C), ephedrine (E) and their combination (C + E) on time to exhaustion during high-intensity exercise. Using a repeated-measures, double-blind design, eight male subjects exercised on a cycle ergometer at a power output that led to exhaustion after about 12.6 min during a placebo (P) control trial. The did this 1.5 h after ingesting either C (5 mg . kg 1(-)), E (1 mg .kg 1 (-)), C + E, or P. Trials were separated by 1 week. Venous blood was sampled before and during exercise. The mean (SD) times to exhaustion were 12.6 (3.1) (P), 14.4 (4.1) (C), 15.0 (5.7) (E) and 17.5 (5.8) (C + E) min. Only the C + E treatment significantly increased time to exhaustion compared to P. Oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE) and the respiratory exchange ratio (RER) were similar during exercise for all trials. Heart rate during exercise was significantly increased for the C + E and C trials compared to P. Subjective ratings of perceived exertion during exercise were significantly lower after C + E compared to P. All treatments significantly increased lactate levels. TRUNCATED
Keywords
Ergogenic aids;Methylxanthine;Sympathomimetic;Physical training
Report Number
DCIEM-96-P-31 — Paper, Reprint
Date of publication
01 Apr 1996
Number of Pages
7
Reprinted from
Eur J Appl Physiol, vol 77, 1998, p 427-433
DSTKIM No
98-01458
CANDIS No
508298
Format(s):
Hardcopy;Document Image stored on Optical Disk

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