Whole body sweat rate prediction: indoor treadmill and cycle ergometer exercise

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Sports Science

Background:

• Accurate hydration management is crucial for athletic performance and health during exercise.
• Existing sweat rate prediction models often lack validation for diverse indoor exercise conditions.
• Individualized sweat rate data is essential for preventing dehydration and heat-related illnesses.

Purpose of the Study:

• To develop and validate accurate prediction equations for whole body sweat rate during indoor cycle ergometer and treadmill exercise.
• To provide a publicly accessible tool for calculating sweat rates based on simple exercise and environmental inputs.

Main Methods:

• Developed proprietary prediction models using data from 112 cycle ergometer trials and 171 treadmill trials across varied temperatures and intensities.
• Validated models using independent datasets of 56 cycle ergometer and 95 treadmill trials.
• Measured whole body sweat rates and incorporated biophysical factors into model development.

Main Results:

• Achieved high prediction accuracy with mean absolute errors of 0.01 L·h⁻¹ (cycle) and 0.02 L·h⁻¹ (treadmill).
• Models explained 92% (cycle) and 78% (treadmill) of the variance between predicted and measured sweat rates.
• Validation confirmed the models' reliability across moderate to high exercise intensities and temperate to hot conditions.

Conclusions:

• The developed prediction equations provide accurate and reliable estimates of whole body sweat rate for indoor cycling and treadmill exercise.
• These equations enable individualized hydration strategies for athletes, coaches, and researchers.
• A publicly available online calculator (https://sweatratecalculator.com) facilitates the practical application of these findings.