Heat loss caused by cooling the feet

Area of Science:

• Physiology
• Environmental Health
• Protective Clothing Technology

Background:

• Heat strain poses a significant risk for individuals working in high-temperature environments, especially when wearing protective clothing.
• Effective thermoregulation strategies are crucial for maintaining worker safety and performance.

Purpose of the Study:

• To investigate the efficacy of foot cooling as a method to alleviate heat strain in subjects wearing chemical protective clothing.
• To determine the optimal timing and duration of foot cooling during physical exertion.

Main Methods:

• Experiment 1: Subjects immersed feet in water (10-30°C) after prolonged sitting in a 35°C environment to measure heat loss.
• Experiment 2: Subjects performed treadmill exercise (5 km/h, 2.5% grade, 90 min) at 35°C wearing protective clothing and water-cooled socks under four cooling conditions.
• Physiological parameters including rectal temperature, skin temperature, and heart rate were continuously monitored.

Main Results:

• Heat loss via the feet was inversely proportional to water temperature, with greater heat loss observed in colder water.
• Cooling the feet during the initial 30 minutes of exercise showed minimal impact on physiological responses.
• Cooling the feet during the final 60 minutes of exercise significantly attenuated increases in core body temperature and heart rate, particularly when core temperatures exceeded 37.5°C.

Conclusions:

• Foot cooling is a viable method for mitigating heat strain in individuals wearing chemical protective clothing.
• Implementing foot cooling during the latter stages of physical exertion is more effective in managing heat strain than early-stage cooling.