Evaluation of the Limits to Accurate Sweat Loss Prediction During Prolong Exercise
Abstract
Sweat prediction equations are often used outside their boundaries to estimate fluid requirements and generate guidance. The limitations associated with these generalized predictions have not been characterized. The purpose of this study were to: 1)evaluate the accuracy of a widely used sweat prediction equation (SHAP) when widening it's boundaries to include cooler environments (2h) and very prolonged exercise (8h), 2) determine the independent impact of holding skin temperature constant (SHAP36), and 3) describe how adjustments for non-sweat losses(NSL) and clothing saturation dynamics effect prediction accuracy. Water balance was measured in 39 volunteers during 15 trails that included intermittent treadmill walking for 2h (300 to 600 W, 15 to 30oC; n=21) or 8h (300 to 420 W, 20 to 40oC; n=18). Equation accuracy was assessed by comparing actual and predicted sweating rates(211 observations) using least-squares regression. Mean and 95% confidence intervals for group differences were compared against a zone of indifference (=/- 0.125 L/h). Sweating rate variance accounted for by SHAP and SHAP36 was always high (r2>0.70), while the standard error of the estimate was small and uniform around the line of best fit. SHAP predictions were > 0.125 L/h during 2h and 8h of exercise. SHAP36 predictions were < 0.125L/h for 2h conditions but were higher at 8h, respectively. These results provide a basis for future development of accurate algorithms with broader utility.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2007
- Accession Number
- ADA472462
Entities
People
- D.a. Goodman
- L. Blanchard
- Michael N. Sawka
- S.j. Montain
- S.n. Cheuvront
Organizations
- United States Army Research Institute of Environmental Medicine