If someone is overheating, move them to a cool area immediately, remove excess clothing, and start cooling their body with water, fans, or ice. Speed matters: the single biggest factor determining how well someone recovers from heat illness is how quickly their body temperature drops. While you’re cooling them, watch for warning signs that separate a manageable situation from a medical emergency.
How to Tell What You’re Dealing With
Heat illness exists on a spectrum, and the actions you take depend on where someone falls on it. The critical dividing line is a core body temperature of 104°F (40°C). Below that, you’re likely dealing with heat exhaustion. Above it, you’re in heat stroke territory, which is a life-threatening emergency.
Heat exhaustion looks like this: pale skin, heavy sweating, muscle cramps, headache, dizziness, nausea, and fatigue. The person may seem wiped out but is still coherent and responsive. Their body is struggling but still fighting to cool itself, which is why they’re sweating so much.
Heat stroke flips several of those signs. The skin turns red and dry because the body has often stopped sweating entirely. Instead of just feeling tired, the person becomes confused, agitated, or aggressive. They may slur their words, hallucinate, or lose consciousness. Seizures can happen. If you see any of these mental changes, call 911 immediately. Do not wait to see if they improve on their own.
Cooling Steps for Heat Exhaustion
For someone who is overheated but still alert and coherent, these steps will bring their temperature down safely:
- Get them out of the heat. Move them indoors to air conditioning, or at minimum into shade. Every minute spent in the heat makes things worse.
- Remove unnecessary clothing, including shoes and socks. Anything trapping heat against the body should come off.
- Apply cool water to the skin. A cool shower, damp towels, or sponging with cool water all work. Fanning them while their skin is wet speeds evaporation, which pulls heat out faster.
- Place cold compresses on high-blood-flow areas. The neck, armpits, and groin are ideal spots because large blood vessels run close to the skin surface there.
- Give them cool fluids. Water or a sports drink with electrolytes, in frequent small sips. Avoid alcohol and caffeine, both of which worsen dehydration.
Stay with the person until they clearly improve. Never leave someone with heat illness alone.
What to Do for Heat Stroke
If the person is confused, unresponsive, has stopped sweating, or shows any change in mental function, treat this as an emergency. Call 911 first. Then cool them aggressively while you wait for help.
The gold standard for rapid cooling is cold water immersion. If you have access to a bathtub, a large tub, or even a tarp you can fill with ice and water, get the person into it. Research consistently shows this is the most effective way to drop core body temperature fast. If immersion isn’t possible, use whatever you have: a garden hose, a cool shower, ice packs on the neck, armpits, and groin, or cool wet sheets draped over the body. Combine methods. Spray them with water while fanning them. The goal is maximum skin contact with something cold.
If the person is conscious and able to swallow, offer chilled water or a sports drink. If they lose consciousness and stop breathing, coughing, or moving, begin CPR.
Red Flags That Mean Call 911
Some symptoms demand emergency medical care regardless of what you think is happening. Call 911 if the person:
- Faints or loses consciousness
- Becomes confused, agitated, or aggressive
- Has a seizure
- Slurs their speech or seems disoriented
- Cannot drink fluids
- Has a body temperature at or above 104°F
Don’t second-guess these signs. Heat stroke can cause permanent brain and organ damage if cooling is delayed. Start cooling the person immediately while waiting for paramedics to arrive.
Common Mistakes to Avoid
One of the most common errors is giving someone an alcoholic beverage to “cool down.” Alcohol accelerates fluid loss and makes dehydration worse. Stick to water or electrolyte drinks only.
Another mistake is waiting too long. People sometimes assume heat illness will resolve on its own if the person just sits in the shade for a while. Heat exhaustion can progress to heat stroke quickly, especially if the person stays warm. Active cooling (applying water, using fans, offering fluids) is always better than passive rest alone. The duration and degree of elevated body temperature is the main predictor of outcome in heat stroke, so every minute of delay in cooling worsens the prognosis.
Salt tablets are also a bad idea. While electrolyte replacement matters, concentrated salt tablets can irritate the stomach and worsen nausea. A sports drink provides a safer electrolyte balance.
Who Is Most Vulnerable
Older adults are at significantly higher risk for heat illness due to several overlapping changes in how the body manages heat. With age, each individual sweat gland produces less sweat, even though the number of active glands stays roughly the same. Blood flow to the skin during heat exposure decreases because the heart pumps less blood outward and the body is slower to redirect blood from the organs to the skin surface. On top of that, older adults often feel less thirsty when dehydrated, so they drink less water than their bodies actually need.
Young children and infants are also at high risk because their bodies generate more heat relative to their size and are less efficient at cooling through sweat. People with chronic conditions like heart disease or diabetes face compounded risk.
Medications are a major and often overlooked factor. Several common drug classes interfere with the body’s ability to regulate temperature. Blood pressure medications like diuretics and beta-blockers can cause dehydration, electrolyte imbalances, and reduced sweating. Antipsychotic medications impair the brain’s temperature regulation center and reduce sweating. Antidepressants, both older tricyclics and newer types, alter sweat production in different ways. Even over-the-counter medications like aspirin can reduce the body’s ability to widen blood vessels near the skin and release heat. If you or someone you’re watching over takes any of these medications, be extra cautious in high heat.
Recovery After Heat Exhaustion
Most people with heat exhaustion feel significantly better within a few hours once they’re cooled down and rehydrated. If treated at a hospital, many go home the same day. But feeling better doesn’t mean fully recovered. The body needs at least 48 hours of rest and continued hydration before returning to physical activity, exercise, or work in the heat. Pushing back too soon increases the risk of a repeat episode.
Heat cramps, which are often the earliest warning sign of heat stress, also call for a two-day break from heavy exertion in hot conditions. Think of cramps as your body’s first alarm. If you ignore them and keep going, heat exhaustion is the next stop on that path, with heat stroke not far behind.
During recovery, drink fluids consistently even if you don’t feel particularly thirsty. Your thirst signal can lag behind your actual hydration needs, especially in older adults. Water is fine for mild cases; a sports drink helps replenish the sodium and potassium lost through heavy sweating.