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How heat affects the body at work
Physical work generates internal heat. When ambient heat, humidity, and clothing limit the body's ability to cool itself, core temperature rises. Performance drops first, then judgment, then safety.
The heat illness spectrum
Heat illness moves on a spectrum: heat rash, heat cramps, heat exhaustion, then heat stroke. Each stage has distinct symptoms and required responses. Heat stroke is a medical emergency.
Individual risk factors
New hires, returning workers, those on certain medications, and workers with chronic conditions face elevated risk. Acclimatization plans must account for these differences.
Controls that actually work
Engineering controls (ventilation, shade structures), administrative controls (work/rest cycles, scheduling), hydration access, and PPE all matter. The combination — not any single control — prevents illness.
Frequently asked questions
- What is the difference between heat exhaustion and heat stroke?
- Heat exhaustion involves heavy sweating, weakness, and nausea. Heat stroke involves confusion, hot dry skin or profuse sweating, and is life-threatening — call emergency services immediately.
- How much water should workers drink in heat?
- OSHA recommends about one cup (8 oz) of cool water every 15-20 minutes during heat exposure, even when workers don't feel thirsty.
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