Heat exhaustion improves quickly when you cool the body down and rehydrate, usually within 30 to 60 minutes of starting treatment. The core body temperature in heat exhaustion typically runs between 101°F and 104°F, and the goal is to bring it back to normal before the condition escalates. Here’s exactly what to do and what to watch for.
Cool Down Immediately
Speed matters. The faster you lower body temperature, the faster symptoms resolve and the less strain your organs take. Follow these steps in order:
- Get out of the heat. Move to an air-conditioned room, a shaded area, or the coolest spot available.
- Lie down and elevate your legs slightly. This helps blood flow back toward your core and brain, reducing dizziness and the risk of fainting.
- Remove extra clothing. Peel off heavy layers, belts, socks, and shoes. Anything tight or unnecessary traps heat against your skin.
- Apply cool water to your skin and fan yourself. Spray, sponge, or splash cool water over as much skin as possible while a fan or breeze blows across you. This combination creates evaporative cooling, which pulls heat from the body far more effectively than air alone.
- Place ice packs on pulse points. The neck, armpits, and groin have blood vessels close to the surface. Ice or cold wet towels in these areas cool circulating blood quickly.
- Sip cool fluids. Water works. A sports drink with electrolytes is even better if you’ve been sweating heavily. Avoid alcohol and caffeine, both of which can worsen dehydration.
If you have access to a bathtub or even a large plastic tub, sitting in cool water is the single most effective cooling method. You don’t need an ice bath for heat exhaustion the way you would for heat stroke, but cool water immersion brings temperature down faster than any other approach.
What Recovery Looks Like
Most people start feeling noticeably better within 15 to 30 minutes of active cooling and rehydration. Nausea fades, the headache loosens, and your heart rate slows back toward normal. Full recovery, where you feel like yourself again, typically takes 24 to 48 hours of rest, steady hydration, and staying in a cool environment.
During that window, your body is still more vulnerable to heat than usual. Avoid exercise, outdoor labor, or anything strenuous for at least 24 hours after symptoms resolve. If you push back into the heat too soon, you’re far more likely to relapse, and the second episode can be worse than the first. Some sports medicine guidelines recommend waiting a full week before returning to intense physical activity in heat, especially if your episode was severe.
Keep drinking fluids steadily over the next day or two even if you feel fine. Rehydration isn’t instant. Your body needs time to restore fluid levels in your blood, muscles, and organs.
Signs It’s Becoming Heat Stroke
Heat exhaustion can tip into heat stroke if cooling doesn’t happen fast enough. Heat stroke is a medical emergency with a fatality rate above 50% if cooling is delayed, but that drops below 5% with rapid treatment within 30 minutes. Know these red flags:
- Body temperature above 104°F. Heat stroke territory begins here, and temperature can climb to 106°F or higher within 10 to 15 minutes.
- Confusion, slurred speech, or delirium. The brain is overheating. This is the clearest sign that heat exhaustion has crossed the line.
- Loss of consciousness.
- Skin that’s hot and red but dry. In heat exhaustion, you’re usually still sweating. When sweating stops and the skin feels dry, the body’s cooling system has failed.
- A fast, pounding pulse.
If any of these appear, call 911. While waiting, cool the person as aggressively as possible. Pour cold water over them, pack ice around the neck, armpits, and groin, and fan constantly. Do not wait for an ambulance to start cooling.
Why Heat Exhaustion Shouldn’t Be Shrugged Off
Even when heat exhaustion resolves without a hospital visit, it puts real stress on your body. Across the spectrum from mild heat illness to severe, injury to the liver, heart, kidneys, and muscles can be present. Research from the University of Florida has found that people who experience serious heat illness are more likely to develop chronic heart and kidney disease later in life, and that changes in the immune system can persist for years afterward.
This doesn’t mean a single mild episode will cause lasting damage. But it does mean repeated bouts of heat exhaustion, common in outdoor workers, athletes, and military personnel, carry cumulative risk. Treating each episode fully and allowing complete recovery before returning to heat exposure protects your long-term health.
Medications That Raise Your Risk
Several common prescription drugs interfere with your body’s ability to handle heat, and many people don’t realize their medication puts them at higher risk. The main categories include:
- Blood pressure medications (diuretics, beta blockers, calcium channel blockers, ACE inhibitors). These can deplete fluids and electrolytes, reduce your thirst signal, limit blood vessel dilation near the skin, and lower blood pressure enough to cause fainting in the heat.
- Psychiatric medications (antipsychotics, antidepressants, ADHD stimulants). Some reduce sweating, others impair the brain’s temperature regulation center, and many cause sedation that makes you less aware of overheating.
- Antihistamines with anticholinergic effects (like diphenhydramine, commonly sold as Benadryl). These decrease sweating and impair your body’s thermostat.
- Common pain relievers like ibuprofen and naproxen, which can reduce kidney blood flow and contribute to dehydration.
If you take any of these, you don’t need to stop your medication in summer. But you do need to be more deliberate about hydration, shade breaks, and recognizing early symptoms. The typical signs of heat exhaustion, heavy sweating, nausea, headache, muscle cramps, dizziness, and fatigue, may appear at lower temperatures or shorter exposure times than they would for someone not on these drugs.
Other Risk Factors
Beyond medications, certain groups are more vulnerable. Adults over 65 have a diminished sweating response and are less likely to feel thirsty. Young children overheat faster because of their smaller body mass. People carrying significant extra weight generate more internal heat during activity. Anyone who isn’t acclimated to hot conditions, such as someone visiting a hot climate or experiencing the first heat wave of the season, is at higher risk because the body hasn’t yet adapted its sweating and blood flow responses.
Dehydration from any cause (a stomach bug, skipping water during a busy workday, a hangover) puts you closer to the threshold before you even step outside. Starting the day well-hydrated is one of the simplest and most effective ways to prevent heat exhaustion entirely.