Heat Strain
Heat stress comes from the environment; heat strain is what happens inside the body. Rising core temperature, faster heart rate, sweating and dehydration are all forms of heat strain.
Scientific detail
Heat strain refers to physiological outcomes — elevated core temperature (T_core), increased heart rate, sweat rate, skin blood flow and dehydration — resulting from heat stress. Predictive human thermoregulatory models such as JOS-3 simulate strain from environmental and metabolic inputs and are used to quantify risk thresholds (e.g. T_core ≥ 38.5 °C for occupational settings).
Related terms
Heat Stress
The thermal load a human body experiences from its environment.
JOS-3
A validated multi-node human thermoregulation model used inside HeatLens.
Thermal Comfort
The condition in which a person is neither too hot nor too cold.
Wet Bulb Globe Temperature
A composite heat index widely used to set safe limits for outdoor work, sport and military training.
Universal Thermal Climate Index
A modern, physiology-based heat index that estimates how the human body actually responds to weather.
Where this concept shows up on MEER
Related publications
Related stories
- Human stories
First-person accounts of life inside extreme heat.
Related resources
In HeatLens
- HeatLens
Interactive heat-risk assessment tool.
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