Heat Overdose: Symptoms, Risks, and What to Do

When your body can’t cool itself down, you’re at risk for heat overdose, a dangerous rise in core body temperature that can lead to organ damage or death. Also known as hyperthermia, it’s not just about feeling hot—it’s when your internal thermostat fails. This isn’t just a summer problem. It happens in gyms, kitchens, factories, and even in poorly ventilated homes during heatwaves.

Heat exhaustion, a milder form of heat overdose, often comes first. You might feel dizzy, nauseous, or sweaty with a rapid pulse. If you ignore it, your body can slide into heat stroke, where sweating stops, skin turns dry and hot, and confusion or loss of consciousness sets in. Dehydration, a key driver of heat overdose, makes this worse—especially if you’re taking diuretics, antihistamines, or blood pressure meds that reduce your body’s ability to regulate fluid. People on antipsychotics or beta blockers are at higher risk too, because these drugs interfere with how your body sweats and responds to heat.

It’s not just about drinking water. Heat overdose is a medical emergency. If someone’s body temperature hits 104°F or higher, their brain and organs start shutting down. Cooling them down fast—ice packs on the neck, armpits, and groin, moving them to shade, calling 911—is critical. Hospitals treat this with IV fluids, monitoring, and sometimes sedation. The longer you wait, the higher the chance of permanent damage.

Some people think heat overdose only happens to athletes or outdoor workers. But it’s also common in older adults, young children, and those on chronic meds. A person on hydrochlorothiazide for blood pressure, for example, might not realize their water pills are making them more vulnerable. Or someone taking levonorgestrel or antipsychotics might have altered sweat responses and not know it.

What you’ll find here are real, practical stories and science-backed advice from people who’ve been there—how to spot early signs, what meds to watch for, how to protect yourself or a loved one, and what steps to take before it’s too late. No fluff. Just what works.