The effects of substrate utilization, manipulated by caffeine, on post-exercise oxygen consumption in untrained female subjects.
The effect of substrate utilization manipulated by caffeine on post-exercise oxygen consumption was investigated in five untrained females (age = 21 +/- 1.5 years), following 90 min of treadmill walking at 55% maximal oxygen consumption. Each subject participated in the two trials (control and experimental) within 2 weeks of each other. Immediately following the measurement of resting oxygen consumption, subjects consumed one of the two test beverages 60 min prior to exercise: 5 mg of caffeine per kg of body-weight in 200 ml of orange juice (CA) or 200 ml of orange juice (C). Assignment of CA and C was made in a random, double blind fashion. Immediately prior to the exercise phase (0 min) resting oxygen consumption was again measured. Following exercise, subjects returned to the same pre-exercise sitting position where respiratory data was collected over 1 h. No significant differences were found in resting oxygen consumption and respiratory exchange ratio (R) prior to caffeine ingestion (-60 min). One hour after caffeine ingestion (0 min) oxygen consumption and free fatty acid (FFA) levels increased significantly compared to C. During and 1 h following exercise, oxygen consumption and FFA levels were significantly greater, with R values being significantly lower in CA compared to C. These findings provide further evidence that metabolic substrate is somehow implicated in elevating oxygen consumption following exercise cessation.
Chad
K
K
Department of Human Movement Studies, University of Queensland, St. Lucia, Australia.
Quigley
B
B
D000328:Adult; D002110:Caffeine / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D012146:Rest / Q000502:physiology; D014692:Ventilation-Perfusion Ratio / Q000502:physiology
D002110:Caffeine