Corrections to the Shapiro Equation used to Predict Sweating and Water Requirements

Abstract

The objective of this project was to cross validate the original Shapiro equation (OSE) which was developed to predict rate of sweat loss over wide environmental conditions, clothing systems, and metabolic activities. activities. Within the limits of the data, the equation has been shown to be a valid estimator of sweating rate for a variety of heat stress exposures up to 2 h and work rates limited to less than 450 W. The second objective was to develop a new prediction algorithm or correct the previous one so that reliable fluid replacement guidelines using such equations can be constructed in the future for more extended work times greater than just 2 h, the exposure time in the original study. The need to develop a new prediction equation stems from results of recent studies at USARIEM that revealed that the original equation embedded in a Heat Strain Decision Aide (HSDA) computer model over predicts actual sweating responses over wide environmental extremes, work rates, and work periods. Overpredictions of sweating rate (and the required fluid intake to fully replace the expected sweat loss) can lead to over-hydration problems. A USARIEM database was secured consisting of 101 volunteer subjects who completed experiments at various activity levels over wide environmental ambient conditions. Subjects wore various military clothing systems including chemical protective clothing and body armor. Each element of the comprehensive heat balance equation was analyzed. Data were analyzed using fuzzy piecewise linear and nonlinear regression analyses to establish appropriate change points in sweat loss per time points. It was established that the original Shapiro algorithm predicts markedly high values in sweating rates. The most important finding of the current study and recommendation is to substitute or modify the current HSDA program with a corrected algorithm.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2008
Accession Number
ADA475891

Entities

People

  • Daniel A. Goodman
  • Larry G. Berglund
  • Laurie A. Blanchard
  • Michael N. Sawka
  • Richard R. Gonzalez
  • Samuel N. Cheuvront

Organizations

  • New Mexico State University

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Body Armor
  • Body Temperature
  • Computers
  • Data Sets
  • Environment
  • Equations
  • Heat Balance
  • Heat Energy
  • Heat Loss
  • Heat Transfer
  • Heat Transfer Coefficients
  • Latent Heat
  • Medical Personnel
  • Protective Clothing
  • Regression Analysis
  • Vapor Pressure
  • Water Vapor

Readers

  • Computational Modeling and Simulation
  • Exercise and Sports Science.