ISSN:
1432-1254
Keywords:
Lower body negative pressure
;
Body temperature
;
Heat loss
;
Heat production
;
Baroreflex
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geography
,
Physics
Notes:
Abstract Changes in body core temperature (T cor) and heat balance after an abrupt release of lower body negative pressure (LBNP) were investigated in 5 volunteers under the following conditions: (1) an ambient temperature (T a) of 20 °C or (2) 35 °C, and (3)T a of 25 °C with a leg skin temperature of 30°C or (4) 35°C. The leg skin temperature was controlled with water perfusion devices wound around the legs. Rectal (T re), tympanic (T ty) and esophageal (T es) temperatures, skin temperatures (7 sites) and oxygen consumption were measured. The intensity of LBNP was adjusted so that the amount of blood pooled in the legs was the same under all conditions. When a thermal balance was attained during LBNP, application of LBNP was suddenly halted. The skin temperatures increased significantly after the release of LBNP under all conditions, while oxygen consumption hardly changed. The release of LBNP caused significant falls inT cor s under conditions (1) and (3), but loweredT cor s very slightly under conditions (2) and (4). The changes inT es were always more rapid and greater than those ofT ty andT re. The falls inT ty andT re appeared to be explained by changes in heat balance, whereas the sharp drop ofT es could not be explained especially during the first 8 min after the release of LBNP. The results suggest that a fall inT cor after a release of LBNP is attributed to an increase in heat loss due to reflexive skin vasodilation and is dependent on the temperature of venous blood returning from the lower body. It is presumed thatT es may not be an appropriate indicator forT cor when venous return changes rapidly.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01241805
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