Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 68: 1889-1895, 1990;
8750-7587/90 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by MacNaughton, K. W.
Right arrow Articles by Graham, T. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by MacNaughton, K. W.
Right arrow Articles by Graham, T. E.

Journal of Applied Physiology, Vol 68, Issue 5 1889-1895, Copyright © 1990 by American Physiological Society

ARTICLES

Influence of caffeine on metabolic responses of men at rest in 28 and 5 degrees C

K. W. MacNaughton, P. Sathasivam, A. L. Vallerand and T. E. Graham
School of Human Biology, University of Guelph, Ontario, Canada.

Cold stress and caffeine ingestion are each reported to increase plasma catecholamines, free fatty acid (FFA) concentrations, and energy metabolism. This study examined the possible interaction of these two metabolic challenges in four double-blind counterbalanced trials. Young adult men (n = 6) ingested caffeine (5 mg/kg) or placebo (dextrose, 5 mg/kg) and rested for 2 h in 28 or 5 degrees C air. Cold stress alone elevated (P less than 0.05) plasma norepinephrine, metabolism (O2 consumption, VO2), and respiratory exchange ratio (RER). Caffeine alone increased (P less than 0.05) plasma epinephrine and FFA but not RER. When the two challenges were combined (caffeine plus 5 degrees C for 2 h) norepinephrine and epinephrine were increased (P less than 0.05) as was FFA. However, VO2, RER, and skin and rectal temperatures were not different from the responses observed at 5 degrees C after placebo ingestion. The data suggest that caffeine selectively increases plasma epinephrine, whereas cold air increases norepinephrine. During the cold exposure, increasing epinephrine and FFA above normal levels did not appear to influence the metabolic or thermal responses to the cold stress. In fact the increase in RER suggested a greater carbohydrate oxidation.


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
F. Haman
Shivering in the cold: from mechanisms of fuel selection to survival
J Appl Physiol, May 1, 2006; 100(5): 1702 - 1708.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
F. Haman, F. Peronnet, G. P Kenny, D. Massicotte, C. Lavoie, and J.-M. Weber
Partitioning oxidative fuels during cold exposure in humans: muscle glycogen becomes dominant as shivering intensifies
J. Physiol., July 1, 2005; 566(1): 247 - 256.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
F. Haman, F. Peronnet, G. P. Kenny, D. Massicotte, C. Lavoie, C. Scott, and J.-M. Weber
Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids
J Appl Physiol, July 1, 2002; 93(1): 77 - 84.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online