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Protection i
Thermal risk does not come only from dramatic weather; ordinary repeated exposure and the quality of the space you live in matter.
Emergency first
Call 911If someone in front of you has these signs now, call the local emergency number first and follow the dispatcher's instructions.
- Heat stroke
A person exposed to heat is confused or delirious, has a seizure, or collapses.
Call emergency services now. Move the person into shade or a cool space and begin cooling while you wait, following dispatcher instructions.
- Hypothermia
Cold exposure with confusion, drowsiness, slurred speech, or shivering that has stopped.
Call emergency services now. Move the person somewhere warm, remove wet clothing, warm them gradually, and do not give alcohol.
- Acute distress
Chest pain, fainting, a person who is unresponsive, or a person who is not breathing normally.
Call the local emergency number immediately. Check responsiveness and breathing, follow the dispatcher, and give only first aid you know or are instructed to provide.
Evolution
Your body holds its temperature within a few degrees, continuously, for a lifetime.
Humans lose heat efficiently through sweating and relatively bare skin. Blood vessels change diameter and shivering produces heat; clothing and shelter complement that regulation.
Humans have an unusual capacity for cooling through sweat
Verified · contestedEccrine-gland density and relatively bare skin make evaporative cooling especially effective compared with many other mammals.
The other sideThe story that these traits evolved specifically for endurance running is contested. The cooling physiology is well supported; the evolutionary narrative remains a hypothesis.
Physiology
Extremes aren't what kill most people — ordinary cold is, because it's far more common. Per day, though, extreme heat is by far the more dangerous.
Moderate cold can dominate population totals because it is much more frequent, while one day of extreme heat can carry much greater risk. Exposure frequency and danger per day are different measures.
In one global study, moderate cold dominated the temperature-attributable total
VerifiedAn analysis of more than 74 million deaths in 384 locations attributed a larger share to cold than heat, especially to frequent moderately cold days.
The other sideThe total does not say how dangerous one day is. Extreme heat can be far more lethal per exposure day, and thermal risk changes with the climate; the cold statistic must not be used to claim warming is protective.
Physiology
Neurological signs make thermal exposure an emergency
VerifiedConfusion, seizures, or collapse in heat can indicate heat stroke; in cold, confusion, drowsiness, slurred speech, or shivering that stops can indicate severe hypothermia.
The other sideAir temperature is not the only factor: humidity limits sweat evaporation, while age, health, and environment change risk.
History
We solved this so well that we forgot it exists.
Housing, clothing, heating, and cooling change real exposure. Risk falls disproportionately on older people, people with chronic conditions, outdoor workers, and those without adequate heating or cooling; it is also an infrastructure issue, not a personal failure.
one small thing
The counter-move
Not heroics, just boring things: don't under-heat your home to save money, dress in layers, and on very hot days spend a few hours somewhere cool and ventilate at night. And check on an older person living alone.
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Safety
the floorRisk is higher for older people, young children, people with cardiovascular or respiratory conditions, outdoor workers, and those without adequate heating or cooling.
Never leave a child or an animal in a parked car, even briefly or with the windows cracked.
Faceva has no body-temperature sensor. It can show surrounding conditions but cannot diagnose heat stroke or hypothermia.
Sauna and cold-plunge protocols are outside this page. If you have a condition for which thermal exposure may matter, ask a clinician first.
Education, not treatment. Faceva does not diagnose, prescribe, or score you.