Cardiovascular Baroreceptors Mediate Susceptibility to Hypothermia
Abstract:Fox WC, Hall C, Hall E, Kolkhorst F, Lockette W. Cardiovascular baroreceptors mediate susceptibility to hypothermia. Aviat Space Environ Med 2003; 74:132–7.
Background: The maintenance of excessively high peripheral blood flow through dilated blood vessels during immersion in cold water could explain some individuals’ predisposition to hypothermia. We hypothesized that interpersonal differences in vascular reactivity could account for contrasting susceptibility to hypothermia. Method: Twenty-two highly fit, volume replete subjects undergoing Navy SEAL training were recruited for this study. Vascular reactivity in these trainees was determined in a thermal-neutral environment by measuring changes in forearm blood flow (FBF) while decreasing their BP with the application of lower body negative pressure (LBNP). FBF was also measured during exposure of these subjects to ice cold water. BP, heart rate, stroke volume, and skin temperatures were also recorded. Results: Changes in FBF induced by a fall in BP correlated with an individual’s reduction in FBF caused by ice water immersion (n = 17, r = 0.84, p < 0.001). A subject’s decrement in BP induced with LBNP correlated inversely with the fall in skin temperature in response to cold water immersion (n = 19, r = 0.70, p < 0.001). Finally, we found that sodium excretion also correlated with cold-induced decrements in peripheral blood flow (n = 7, r = 0.83, p < 0.05). Conclusions: It is suggested that contrasting cardiovascular baroreceptor sensitivity and vascular responsiveness contribute to individual differences in susceptibility to hypothermia. Furthermore, the trend toward dietary salt restrictions may not be salutary in the Navy SEAL who must frequently operate in cold ambient environments.
Document Type: Research Article
Publication date: February 1, 2003
More about this publication?
- The peer-reviewed monthly journal, Aviation, Space, and Environmental Medicine (ASEM) provides contact with physicians, life scientists, bioengineers, and medical specialists working in both basic medical research and in its clinical applications. It is the most used and cited journal in its field. ASEM is distributed to more than 80 nations.
To access volumes 86 to present, please click here.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- Submit Articles
- Ingenta Connect is not responsible for the content or availability of external websites