Journal article
Thermal adjustments to nonexertional heat stress in mature and senescent Fischer 344 rats
Journal of applied physiology (1985), Vol.68(4), pp.1337-1342
04/1990
DOI: 10.1152/jappl.1990.68.4.1337
PMID: 2347776
Abstract
The purpose of this study was to test the hypothesis that the rise in colonic temperature (Tc) during nonexertional heat stress is exaggerated in senescent (SEN, 24 mo, n = 12) vs. mature (MAT, 12 mo, n = 15) conscious unrestrained Fischer 344 rats. On 2 separate days (48 h apart) each SEN and MAT animal was exposed to an ambient temperature (Ta) of 42 degrees C (relative humidity 20%) until a Tc of 41 degrees C was attained and then cooled at a Ta of 26 degrees C until Tc returned to the initial control level. Control Tc was similar in the two groups for both trials. The rate of Tc change during heating was 63% greater (0.070 +/- 0.005 vs. 0.043 +/- 0.004 degrees C/min, P less than 0.05) and the time to 41 degrees C reduced by 36% (54 +/- 6 vs. 85 +/- 10 min, P less than 0.05) in MAT vs. SEN animals during the first exposure, although the cooling rate was slower in the MAT (0.048 +/- 0.004 degrees C/min) vs. SEN (0.062 +/- 0.006 degrees C/min) animals (P less than 0.05). The heating rate was unchanged in MAT animals between trials 1 and 2. However, SEN animals had a 95% increase in heating rate in trial 2 compared with trial 1 (P less than 0.05), and the corresponding time to 41 degrees C was decreased by 44% (P less than 0.05). As a result, rate of heating and time to 41 degrees C were similar in the two groups during trial 2. The cooling rate was similar between trials within each group.
Details
- Title: Subtitle
- Thermal adjustments to nonexertional heat stress in mature and senescent Fischer 344 rats
- Creators
- Kevin C Kregel - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721Charles M TiptonDouglas R Seals
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.68(4), pp.1337-1342
- DOI
- 10.1152/jappl.1990.68.4.1337
- PMID
- 2347776
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Grant note
- HL-39966 / NHLBI NIH HHS AG-00423 / NIA NIH HHS HL-07574 / NHLBI NIH HHS
- Language
- English
- Date published
- 04/1990
- Academic Unit
- Radiation Oncology; Provost Office Administration; Health and Human Physiology
- Record Identifier
- 9984213310502771
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