Study Overview
Objective: To understand when the human body can no longer maintain core temperature (i.e., when thermoregulation fails) under extreme heat and humidity.
Conducted using volunteers subjected to:
Various temperature-humidity combinations.
Followed by prolonged exposure slightly above their thermoregulatory threshold.
Key Findings
Human ability to maintain stable core body temperature in extreme heat is lower than previously believed.
In conditions of:
42°C temperature with 57% relative humidity,
Core body temperature rose continuously (streamed upwards).
Participants could not complete the 9-hour exposure.
Thermoregulation failed → body unable to release heat effectively.
Significance
Challenges earlier assumptions about human heat tolerance.
Important for occupational health, especially:
Outdoor laborers (e.g., construction, agriculture).
Military personnel, athletes, elderly.
Heatwaves and climate change increase such health risks.
What is Thermoregulation?
The process by which the body maintains a stable internal temperature (around 37°C).
Achieved through mechanisms like:
Sweating, vasodilation, behavioral responses (seeking shade, reducing activity).
Fails when heat gain > heat loss.
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