Caffeine is ergogenic after supplementation of oral creatine monohydrate

• Published in: Medicine and science in sports and exercise 2002-11, Vol.34 (11), p.1785-1792
• Main Authors: DOHERTY, Mike, SMITH, Paul M, DAVISON, R. C, HUGHES, Michael G
• Format: Article
• Language: English
• Subjects: Adult; Anaerobic Threshold - drug effects; Anaerobic Threshold - physiology; Analysis of Variance; Biological and medical sciences; Blood Chemical Analysis; Blood Gas Analysis; Caffeine - administration & dosage; Central Nervous System Stimulants - administration & dosage; Creatine - administration & dosage; Dietary Supplements; Double-Blind Method; Energy Metabolism - physiology; Exercise Test; Humans; Male; Medical sciences; Muscle Fatigue - physiology; Neuropharmacology; Pharmacology. Drug treatments; Physical Endurance - drug effects; Physical Exertion - drug effects; Physical Exertion - physiology; Probability; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Reference Values; Running - physiology; Sensitivity and Specificity; Space life sciences
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1097/00005768-200211000-00015

The purpose of this investigation was to assess the acute effects of caffeine ingestion on short-term, high-intensity exercise (ST) after a period of oral creatine supplementation and caffeine abstinence. Fourteen trained male subjects performed treadmill running to volitional exhaustion (T(lim)) at an exercise intensity equivalent to 125% VO(2max). Three trials were performed, one before 6 d of creatine loading (0.3 g x kg x d(-1) baseline), and two further trials after the loading period. One hour before the postloading trials, caffeine (5 mg x kg(-1)) or placebo was orally ingested in a cross-over, double-blind fashion. Four measurements of rating of perceived exertion were taken, one every 30 s, during the first 120 s of the exercise. Blood samples were assayed for lactate, glucose, potassium, and catecholamines, immediately before and after exercise. Body mass increased (P < 0.05) over the creatine supplementation period, and this increase was maintained for both caffeine and placebo trials. There was no increase in the maximal accumulated oxygen deficit between trials; however, total VO(2) was significantly increased in the caffeine trial in comparison with the placebo trial (13.35 +/- 3.89 L vs 11.67 +/- 3.61 L). In addition, caffeine T(lim) (222.1 +/- 48.9 s) was significantly greater (P < 0.05) than both baseline (200.8 +/- 33.4 s) and placebo (198.3 +/- 45.4 s) T(lim). RPE was also lower at 90 s in the caffeine treatment (13.8 +/- 1.8 RPE points) in comparison with baseline (14.6 +/- 1.9 RPE points). As indicated by a greater T(lim), acute caffeine ingestion was found to be ergogenic after 6-d of creatine supplementation and caffeine abstinence.