Effects of Theophylline Ingestion on Thermoregulation During 15 deg C water Immersion
Abstract
Military personnel can be exposed to emergency survival conditions in cold environments which could result in lethal levels of hypothermia if appropriate insulation or protective shelters are not available. Hypothermia can be delayed in humans if metabolic heat production is increased, and we have previously demonstrated that pretreatment with certain safe pharmacological agents can elicit such an effect. Others have reported that the ingestion of theophylline, a caffeine-like compound, delays the onset of hypothermia during acute cold air exposure. The present study was carried out to determine if theophylline treatment will delay the onset of hypothermia during a more severe cold stress, i.e. cold water immersion. Eight male subjects were immersed in 15 deg C water on several different days after treatment with placebo, theophylline, or either of these combined with a standard meal. Although there were indications that the theophylline treatment, particularly when combined with the meal, increased metabolic heat production prior to immersion, there were no significant differences between trials in metabolic heat production during the water immersion. Rectal temperature decreased similarly in all trials at a rate ranging between 0.4 to 3.0 deg C/h. Thus, the beneficial effects of theophylline treatment that were previously reported for cold air exposure may not be applicable to cold water immersion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1994
- Accession Number
- ADA286280
Entities
People
- Ira Jacobs
- John Frim
- Larry C. Wang
- Margaret F. Kavanagh
- T. Romet
Organizations
- DRDC Toronto