Heat and Cold: Knowing Your Limits

Why this matters

Heat and cold do not feel like emergencies until they already are one. Heat illness clouds your judgment before it drops you, which is why people keep working right up to the point they collapse. Cold does the same in reverse, numbing you and slowing your thinking. Both are completely preventable, and both kill field workers every year in attics, crawlspaces, rooftops, and unheated job sites. Knowing your limits is a skill, not a weakness.

How heat hurts you, in stages

Heat illness is a ladder. Catch it on the lower rungs, because the top one can be fatal.

• Heat cramps. Painful muscle spasms, usually legs or abdomen. An early warning that you are low on water and electrolytes.
• Heat exhaustion. Heavy sweating, weakness, dizziness, nausea, headache, clammy and pale skin. You can still function, barely, which is the danger. This is the stop-now point.
• Heat stroke. A true emergency. The body stops cooling itself. Skin may be hot and dry or still sweaty, confusion sets in, behavior gets strange, and the person may pass out. Call for emergency help immediately, move them to shade, and cool them fast with water and air while you wait.

The warning sign to respect most is confusion or a coworker "acting off." By the time judgment is affected, the person cannot reliably save themselves.

Working in heat without going down

• Hydrate before you are thirsty. Thirst lags behind dehydration. Small amounts of water often beats chugging once. On long hot days, add electrolytes, not just plain water.
• Use the cooler hours. Schedule the hardest, hottest work, the attic, the roof, the sealed mechanical room, for early morning when you can.
• Acclimatize. The first hot days of the season and a new worker's first week are the highest risk, because the body has not adjusted. Build up exposure gradually.
• Take shade breaks before you need them. A short rest in the shade resets your core temperature. Skipping breaks to "finish faster" is how exhaustion turns into stroke.
• Watch each other. On a crew, you will spot a buddy's slurred speech or stumble before they notice it themselves.

Attics and crawlspaces deserve special caution. They can run far hotter than the air outside, with no airflow and no easy exit. Limit time inside, take water in with you, and tell someone you are going in.

How cold hurts you

Cold has its own ladder, and wet or windy conditions make it climb much faster.

• Cold stress and early hypothermia. Shivering, numb fingers, clumsiness, slowed thinking. Your dexterity drops, which is its own hazard around tools and ladders.
• Worsening hypothermia. Shivering may stop, confusion deepens, and the person grows drowsy. Stopping shivering is a bad sign, not a good one. Get them warm and seek medical help.
• Frostbite. Skin goes white, gray, or waxy and numb, usually fingers, toes, ears, nose. Do not rub it. Warm it gently and get medical care.

Working in cold safely

• Layer, and manage sweat. Multiple light layers beat one heavy coat because you can adjust. Sweat that soaks your base layer will chill you hard once you stop moving, so vent before you overheat.
• Protect the extremities. Most heat loss and most cold injury hit hands, feet, and head. Insulated, dry gloves and a hat do the heavy lifting.
• Stay dry. Wet is the multiplier. A waterproof shell and dry spare gloves change everything.
• Warm up on a schedule. Cycle into a heated truck or space before your hands stop working, not after.
• Mind the surfaces. Cold brings ice. The slip risk on ladders, roofs, and steps rises with the cold, so slow down.

The judgment rule for both extremes

Heat and cold both attack the exact tool you need to make good safety decisions: your judgment. So set the limits while you are still clear-headed, at the start of the day, and honor them even when you feel fine. "I will stop when I feel bad" fails because feeling bad comes after your thinking is already impaired. Plan the breaks, plan the water, plan the warm-up, and do not let the schedule talk you out of them.

References

• OSHA heat-illness prevention guidance (water, rest, shade, acclimatization)
• OSHA and NIOSH cold-stress and hypothermia prevention material
• National Weather Service heat index and wind chill references
• See related: Situational Awareness on a Job Site; Mental Health and Jobsite Safety