Heat exhaustion and heat stroke: how to recognize them and what to do

Puerto Rico’s Department of Health explains that the body cools itself by sweating, but in some conditions sweating isn’t enough and body temperature rises fast. Heat stroke happens when the body can no longer control its temperature, and it can cause death or permanent disability. Heat exhaustion is the body’s response to losing too much water and salt through sweat; it is milder, but it can get worse if it isn’t treated.

There are also heat cramps: painful cramps or spasms in the belly, arms or legs in people who sweat a lot during hard work or exercise. If you get cramps outside the heat too, see muscle cramps. And according to the CDC, heavy sweating in hot, humid weather also causes heat rash: red clusters of pimples or small blisters on the neck, chest, groin or skin folds.

According to the CDC and the Department of Health, the signs of heat stroke are:

Call [911](tel:911). Until help arrives, according to the CDC:

• Stay with the person until help arrives.
• Move them to a cool, shaded area.
• Remove extra clothing.
• Cool them quickly: with cold water or an ice bath if possible, or cold, wet cloths on the skin, and fan them.
• Put cold, wet cloths or ice on the head, neck, armpits and groin.

According to the CDC’s NIOSH, in heat stroke body temperature can rise to 106 °F (41 °C) or higher within 10 to 15 minutes, and it can be fatal if treatment is delayed. That is why you cool the person without waiting.

MedlinePlus warns not to give acetaminophen or aspirin, alcohol or salt tablets, and not to give anything by mouth if the person is vomiting or unconscious.

According to the CDC and the Department of Health, heat exhaustion causes:

The Department of Health advises resting in a cool place, drinking plenty of water or another cool drink, and taking a cool shower or sponge bath. For cramps, stop all activity, sit somewhere cool, and drink water with food or a sports drink.

If you don’t improve with shade, rest and fluids, if you get worse, or if you are vomiting and can’t keep fluids down, get medical care. If confusion or fainting appears, it has become heat stroke: call 911. If you have gone hours drinking too little, see also dehydration in adults.

A video visit helps when there are no heat stroke signs (with heat stroke, call 911): for example, you have recovered from heat exhaustion and want to know when you can go back to work or sports, you keep getting cramps or headaches, or you want to check whether your medicines raise your risk in the heat. You see Dr. Diana Nieves Castro, a Puerto Rico–licensed general practice physician with several years of emergency-department experience.

We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you. If appropriate, the doctor prescribes and we send your prescription to your pharmacy. This is virtual urgent care for problems that are not emergencies. On vacation here? See our care for visitors.

A doctor visit has the same price for every age, with no membership; your card is charged when you request it, with a full refund if the clinic can’t see you. Doctor online 24/7: video doctor visits around the clock. Book online and choose your time right away. We send you a secure video link that works on your phone, tablet or computer. For patients under 21, a parent or legal guardian stays on camera with photo ID. You need to be physically in Puerto Rico during the visit. Book your visit.

The CDC warns that some medicines raise the risk of heat illness because they affect sweating, thirst, blood pressure or the body’s salts. They include diuretics (“water pills”), some blood pressure medicines (beta blockers, ACE inhibitors and angiotensin receptor blockers), certain antidepressants, antipsychotics, antihistamines, anticholinergics and stimulants. A diuretic combined with one of those blood pressure medicines raises the risk further.

Don’t stop your medicines on your own. Ask the doctor whether your treatment needs adjusting in the hot months; if you have a chronic condition, see chronic care.

According to the Department of Health’s syndromic surveillance, between weeks 1 and 36 of 2026 there were 442 emergency-room visits for heat- or light-related illness, peaking in week 27 (28 visits). 33 of those visits were by people who don’t live in Puerto Rico. Only 29 ERs and urgent care centers (about 15.5%) send this data, so the real number is higher.

Heat is most dangerous for older adults, young children, and people who are sick or overweight, according to the Department of Health; the CDC adds pregnant women, people with heart disease, children with asthma, outdoor workers and athletes.

According to the Department of Health:

With any of these signs, call 911 or go to an emergency room. Don’t book a video visit. See when to go to the ER.