Heat exhaustion vs. heat stroke
Heat exhaustion is a warning. Heat stroke is a life-threatening emergency. Knowing the difference, and acting fast, saves lives.
Heat exhaustion
Look for:
- Heavy sweating
- Cold, pale, clammy skin
- Fast, weak pulse
- Nausea or vomiting
- Muscle cramps
- Tiredness, weakness, dizziness, headache
- Fainting
Do this:
- Move to a cool place, ideally air-conditioned
- Loosen tight clothing
- Apply cool, wet cloths or take a cool bath
- Sip water
Get medical help right away if they're vomiting, symptoms get worse, or symptoms last longer than an hour.
Heat stroke
Look for:
- Body temperature of 103°F or higher
- Hot, red, dry or damp skin
- Fast, strong pulse
- Headache, dizziness, nausea
- Confusion or acting "not themselves"
- Losing consciousness (passing out)
Do this:
- Call 911 immediately.
- Move them somewhere cooler (shade, indoors, AC).
- Cool them fast: cold water, ice packs on neck, armpits, and groin, wet sheets plus a fan, or immersion in cool water if available.
- Do not give them anything to drink.
Symptoms adapted from the CDC: Heat-Related Illnesses and Maricopa County: Signs of Heat Illness.
Hydration
- Drink before you're thirsty. Thirst is a late signal, especially for older adults.
- Sip steadily through the day instead of chugging large amounts at once.
- Replace electrolytes if you're sweating heavily for long periods (outdoor work, yard work, walking). Electrolyte drinks or tablets help; water alone isn't always enough.
- Limit alcohol and stimulants. They make it harder for your body to handle heat.
- Check your urine: pale yellow is good; dark yellow means drink more.
- Carry water every time you leave home, even for "quick" errands. Car breakdowns and bus delays happen.
- If your doctor limits your fluids or you take diuretics, ask them how to adjust in extreme heat.
Cooling strategies, with or without power
Cool your body
- Wet your skin and clothes, then sit in moving air (fan, breeze, or fanning by hand).
- Cool water on wrists, neck, and feet; a wet bandana or cooling towel on your neck.
- Cool (not ice-cold) showers or foot soaks.
- Loose, light-colored, breathable clothing. Outside in the sun? Cover up loosely: see To Cover Up, Or Not?
- Rest during 10 a.m. to 6 p.m.; do chores at dawn.
Cool your space
- Close blinds and curtains on sun-facing windows during the day; reflective window film or foil helps a lot.
- Stay on the lowest floor and in interior rooms.
- Open windows only when it's cooler outside than inside (usually pre-dawn).
- Avoid using the oven or stove; eat cold meals.
- Once indoor temps get very high, fans alone can't keep you safe. That's the time to go to a cooling center or somewhere with AC.
If your AC fails in summer, treat it as an emergency. Call your landlord or a repair service right away, and go somewhere cool while you wait. In 2025, among indoor heat deaths in Maricopa County where an AC unit was present, the unit wasn't working in 72% of cases (MCDPH).
Who's most at risk, and how to help
Older adults
Bodies regulate heat less well with age, and many medications affect heat tolerance. Check in at least twice a day during heat warnings. Make sure AC works and that they'll actually use it, since cost worries keep some people from running it. Point them to energy assistance programs.
Babies & kids
Children heat up faster and can't always tell you something's wrong. Watch for fussiness, lethargy, or fewer wet diapers. Never leave a child in a car. Check playground slides and surfaces before kids touch them.
People experiencing homelessness
Nearly half of heat deaths in Maricopa County are among unhoused people. Offer water, electrolytes, and directions to the nearest heat relief site. If someone seems confused or unresponsive in the heat, call 911.
Outdoor workers
Construction, landscaping, delivery, and other outdoor workers: schedule hard work early, take shade and water breaks, use the buddy system, and ease back in after time away (your body needs days to acclimatize). Know your rights at OSHA: Heat.
People with health conditions
Heart disease, diabetes, kidney disease, mental illness, and substance use all raise risk. Some medications (like diuretics, some blood pressure and psychiatric medications) affect heat tolerance. Ask your doctor or pharmacist.
Pets
Pavement can burn paws. Walk dogs at dawn or after dark, test the ground with the back of your hand, and keep plenty of shade and water. Never leave pets in a parked car. Panting heavily, drooling, or stumbling are emergency signs; call a vet.
Cars, pavement & hot surfaces
- Never leave a child, older adult, or pet in a parked car, not even for a minute, and not even with windows cracked. Car interiors heat up dangerously fast.
- "Look before you lock." Put your bag or phone in the back seat as a reminder to check for kids.
- If you see a child or pet alone in a hot car, call 911.
- Keep a car heat kit: extra water, a sunshade, a cooling towel, and a phone charger. A breakdown on a desert road can become dangerous fast.
- Keep your gas tank above half in summer so you can run the AC if you're stuck.
- Asphalt, concrete, metal, and car surfaces can cause serious burns, especially if someone falls or collapses on them. Move a person who's down off hot pavement as soon as it's safe.
Check on your neighbors
In Maricopa County's 2025 report, 48% of indoor heat deaths were discovered during a welfare check, when a neighbor, family member, or EMS was called to check on someone. Earlier check-ins can turn a tragedy into a rescue.
- Make a short list of people to check on: older neighbors, people who live alone, anyone with a disability or illness, and families with newborns.
- Exchange phone numbers before summer and agree on a daily check-in time during heat warnings.
- Ask directly: "Is your AC working? Is it running? Is it cool inside?"
- If no one answers and you're worried, call 911 for a welfare check.
- See Community & Conflict for more on organizing neighbors.
Maricopa County cooling & hydration resources
Heat Relief Network
Find cooling centers, hydration stations, and donation sites near you on the regional map, run by the Maricopa Association of Governments.
Dial 2-1-1
Arizona's free, confidential line for community resources, including cooling centers, shelter, food, and utility help.
Maricopa County: Extreme Heat
Official county heat resources, illness prevention tips, and data.
City of Phoenix Office of Heat Response
City heat programs, cooling centers, and heat response updates.
NWS Phoenix heat forecasts
HeatRisk forecasts and Extreme Heat Warnings for the Phoenix area.
Energy bill help
Utility assistance and energy programs for seniors and low-income households.
Why this matters
Maricopa County Department of Public Health (MCDPH) says it plainly: all heat-related deaths are preventable. Yet heat deaths in the county climbed sharply over the past decade.
Heat-related deaths in Maricopa County, 2015 to 2025
Source: MCDPH, 2025 Heat-Related Deaths Report (published April 2026). Includes heat-caused and heat-contributed deaths.
What the data tells us
- Most deaths happen outdoors: 74% of 2025 heat deaths occurred outdoors.
- Age matters: about 60% of those who died were 50 or older, and roughly 3 out of 4 were men.
- Broken AC is deadly: among indoor deaths with an AC unit present, it wasn't functioning in 72% of cases. About 23% of indoor deaths happened in mobile homes or RVs/trailers.
- Substances raise risk: 55% of 2025 heat deaths involved substance use.
- "Moderate" heat days still kill: 47% of 2025 heat deaths occurred on days when the NWS heat risk level was only moderate.
- Phoenix is getting hotter: in 2024 Phoenix set records with 113 consecutive days at or above 100°F (May 27 to Sept 16) and 70 days at or above 110°F in one year (NWS Phoenix).
- Prevention is working: deaths fell from 645 (2023) to 608 (2024) to 430 (2025), even as heat records keep falling. Cooling centers, outreach, and neighbors checking on neighbors matter.
Sources
- Maricopa County Department of Public Health, 2025 Heat-Related Deaths Report (April 2026).
- Maricopa County Department of Public Health, 2024 Heat-Related Deaths Report (final, 2025).
- Maricopa County, Heat Surveillance & Reports (weekly dashboard during heat season).
- National Weather Service Phoenix, Historical Extreme Temperatures in Phoenix.
- Centers for Disease Control and Prevention, Heat-Related Illnesses: Signs and Symptoms.