Serum S-100 Beta Response to Exercise-Heat Strain Before and After Acclimation
Abstract
Exercise alone or in combination with environmental heat stress can elevate blood S-100 beta protein concentrations. However, the explanatory power of exercise with marked environmental heat stress on the appearance of S-100 beta is questionable. It is possible that the process of heat acclimation might afford additional insight. Purpose: Determine the S-100 beta response to moderate intensity exercise with heat strain before and after heat acclimation. Methods: Nine healthy male volunteers completed 10 consecutive days of heat acclimation consisting of up to 100 minutes of treadmill walking 91.56 m/s, 4% grade) in the heat (45 deg C, 20% relative humidity). Changes in heart rate (HR), rectal temperature (Tre), and sweat rate (SR) were examined to determine successful acclimation. Area under the curve (AUC) for Tre > 38.5 deg C was calculated to assess cumulative hyperthermia. Blood samples were taken before and after exercise on days 1 and 10 and analyzed for serum osmolality and S-100 beta concentration. Results: All subjects displayed physiological adaptations to heat acclimation, including a significant (P< 0.05) reduction in final HR (161 to 145 b/mm) and Tre (39.0 to 38.4 C), as well as a modest (approx. 10%) increase in SR (1.10 to 1.20 L/hr; p=0.09). No differences were observed in pre-to-post exercise serum S-100 beta concentrations on day 1 or day 10, nor were differences observed in S-100 beta values between days 1 and 10. No significant correlations were found between S-100 beta values and any variable of interest. Conclusions: S-100 beta concentrations do not necessarily increase in response to exercise heat strain and no effect of heat acclimation on S-100 beta could be observed despite other quantifiable physiological adaptations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2008
- Accession Number
- ADA484458
Entities
People
- Brett R Ely
- Daniel A. Goodman
- James P. Mcclung
- Michael N. Sawka
- Robert W. Kenefick
- Samuel N. Cheuvront
- Troy D. Chinevere
Organizations
- United States Army Research Institute of Environmental Medicine