Measurement of sweating rate with capacitance sensors

Area of Science:

• Human physiology
• Biomedical engineering

Background:

• Accurate measurement of local sweat gland activity is crucial for understanding thermoregulation and various physiological conditions.
• Existing methods for sweat analysis can be complex, expensive, or lack portability.

Purpose of the Study:

• To introduce a new, self-contained, portable, and inexpensive forced-evaporation skin capsule for measuring local human sweat gland activity.
• To detail the construction and calibration challenges of this novel sweat measurement device.

Main Methods:

• A forced-evaporation technique using a stream of dry nitrogen gas to evaporate sweat from the skin surface.
• Integrated measurement of relative humidity and temperature changes within the capsule using thin-film capacitance sensors and solid-state devices.
• On-line microcomputer for data acquisition and evaporation rate calculations, eliminating the need for external vapor analyzers.

Main Results:

• The described capsule is self-contained, portable, and cost-effective.
• It is suitable for use in arrays for simultaneous measurements on adjacent skin areas.
• The system allows for direct measurement of sweat evaporation rates without external equipment.

Conclusions:

• The developed forced-evaporation skin capsule offers a practical and efficient method for assessing local sweat gland function.
• Its design facilitates widespread application in physiological research and clinical diagnostics requiring sweat analysis.