Effects of ephedrine/xanthines on thermogenesis and cold tolerance.
This paper reviews the use of ephedrine (E) and xanthines (X) to improve thermogenesis and cold tolerance. Recent experiments in cold-exposed subjects have shown that the beneficial effects of ingesting an E/caffeine (C) capsule on metabolic rate (M), heat debt, deep body core temperature (Tre) (P < 0.05) is entirely comparable to that observed with an E/C/theophylline (T) capsule. Although T has been reported to reduce the drop in Tre in several studies, these improvements are difficult to explain in the absence of changes in M. A theobromine-based commercial sports bar (Cold Buster) has been similarly shown to reduce the drop in Tre. However, such a claim could not be confirmed in our lab, even in two studies performed under different environmental conditions. Despite an increase in M in some studies, C had no effect on Tre in the cold. It is concluded that E/X represent, at the moment, the best pharmacological agents to enhance cold thermogenesis and to delay the onset of hypothermia in humans.
Defence & Civil Institute of Environmental Medicine, Environmental Physiology Section, Toronto, Ontario, Canada.
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D001481:Basal Metabolism / Q000187:drug effects; D001831:Body Temperature; D001833:Body Temperature Regulation / Q000187:drug effects*; D003080:Cold Temperature; D004311:Double-Blind Method; D004809:Ephedrine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010919:Placebos; D014970:Xanthines / Q000494:pharmacology*
D010919:Placebos; D014970:Xanthines; D004809:Ephedrine