The sweating foot: local differences in sweat secretion during exercise-induced hyperthermia.

Area of Science:

• Physiology
• Thermoregulation
• Human Physiology

Background:

• Local differences in foot sweat secretion are not well understood.
• This knowledge is crucial for accurate thermoregulatory modeling.
• Understanding sweat patterns aids in footwear design.

Purpose of the Study:

• To investigate local differences in foot sweat secretion.
• To quantify sweat rates across various foot regions.
• To compare foot sweat rates with forehead sweat rates.

Main Methods:

• Investigated local sweat rates across core temperatures (37-39°C) using cycling and a heat-perfusion garment.
• Measured sweat rates on the forehead and multiple foot sites (dorsal, lateral, plantar) in six healthy adults.
• Utilized 3.16 cm² capsules for sweat collection.

Main Results:

• Foot sweat rates were generally less than 50% of forehead sweat rates.
• Specific foot sites showed varying sweat outputs: dorsal 1 (38%), dorsal 2 (54%), dorsal 3 (37%), lateral (24%), and plantar (18%).
• Average sweat rates (mg cm⁻² min⁻¹): forehead (2.61), dorsal 1 (0.98), dorsal 2 (1.39), dorsal 3 (0.95), lateral (0.62), plantar (0.47).

Conclusions:

• Average foot sweat secretion was 30 ml/h, peaking at 50 ml/h.
• Approximately 70% of measured sweat originated from the upper foot surfaces, with only 30% from the plantar surface.
• Highlights significant regional variation in foot sweat production.