Heat exhaustion is a serious warning that the body's cooling system is struggling. Signs include heavy sweating, cool/pale/clammy skin, rapid weak pulse, nausea, muscle cramps, weakness, and dizziness. Move the worker to a cool environment immediately, loosen clothing, apply cool wet cloths, and provide fluids if conscious.

Heat stroke is a life-threatening emergency. Signs include high body temperature (103°F or higher), hot/red/dry or damp skin, rapid strong pulse, confusion, loss of consciousness, and the worker may stop sweating entirely. Call 911 immediately. Cool the worker rapidly by any means available — cold water immersion is the most effective. Do not give fluids if the person is unconscious.

OSHA recommends that workers in hot conditions drink approximately 1 cup (8 oz.) of water every 15–20 minutes — about 24 oz. per hour — rather than large amounts infrequently. Thirst is a poor indicator of dehydration; by the time a worker feels thirsty, they may already be 1–2% dehydrated, which measurably impairs physical and cognitive performance.

For work lasting longer than 1 hour in hot conditions, water alone may be insufficient — electrolyte replacement is needed. Sqwincher provides sodium, potassium, and other electrolytes lost through sweat. Avoid caffeinated beverages and energy drinks, which can increase dehydration risk.

Evaporative cooling products use the physical process of evaporation to lower temperature. Water evaporating from a surface absorbs heat energy from that surface to change state from liquid to vapor — this is the same mechanism as sweating.

Chill-Its® Cooling Towels use a super-evaporative PVA (polyvinyl alcohol) material that holds more water and evaporates more slowly than cotton, maintaining a surface temperature below ambient air temperature for an extended period. Cooling bandanas and hard hat pads use polymer crystals that absorb water and release it slowly as they evaporate.

These products are most effective in low-humidity environments. In high-humidity conditions, the air is already saturated with moisture and evaporation slows — active cooling methods (shade, air movement, cold water immersion) become more important.

Any worker can develop heat illness, but risk is significantly higher for:

• New workers — the body takes 7–14 days to acclimatize to heat through a process that increases sweat rate and reduces electrolyte loss. New hires and returning seasonal workers are at the highest risk in their first two weeks.
• Workers in full PPE — arc flash suits, chemical protective coveralls, and heavy FR clothing significantly reduce the body's ability to cool itself through sweating and convection.
• Workers with medical conditions — heart disease, obesity, uncontrolled diabetes, and certain medications (diuretics, antihistamines, antidepressants) impair heat tolerance.
• Outdoor workers in direct sun — solar radiation adds 10°F to the effective heat index calculation.