Caffeine Attenuates the Afterdrop in Rectal Temperature After Mild Cooling
NAVAL MEDICAL RESEARCH INST BETHESDA MD
Pagination or Media Count:
Previous research has shown that subjects who experience immersion hypothermia often show a continued decreased in rectal temperature afterdrop during the initial phase of rewarming. Because caffeine, the principal constituent of coffee, influences thermoregulatory and cardiovascular responses and is occasionally administered to individuals upon removal from cold exposure, we examined whether caffeine might influence rewarming after mild cooling. Seven male subjects were given either warm decaffeinated coffee containing 3.5 mgkg caffeine or warm water after their rectal temperature was reduced by 0.5 C via immersion in cold 13 C water. Between 20 and 40 minutes min after removal from cold water a o.8 C afterdrop in rectal temperature occurred in the noncaffeine control condition, while the condition administered caffeine showed a mean afterdrop of 0.5 C. After 120 min, the caffeine condition had rewarmed back to the pre-afterdrop criterion, while the control condition was still 0.5 below the criterion level. These data indicate that caffeine significantly attenuated the magnitude of the post-immersion afterdrop in rectal temperature.
- Medicine and Medical Research