If a person exposed to heat develops neurological symptoms such as confusion, gibberish, convulsions, or decreased responsiveness, heatstroke should be suspected and 119 should be called immediately. Even if the patient is conscious, if there is severe weakness, dizziness, or vomiting, it may be heat exhaustion, so medical evaluation is necessary if the patient does not improve quickly even after cooling and rehydration.
Although the two conditions have similar names, they pose very different risks. Heat exhaustion usually improves with rest and fluids in a cool place, but heatstroke is a condition in which the body temperature regulation function itself is broken, so the longer treatment is delayed, the higher the death rate. The distinction criteria and treatment order are summarized below.
Summary
- Confusion, convulsions, and decreased consciousness are key emergency signs of possible heatstroke.
- Heatstroke: A medical emergency involving high body temperature and central nervous system dysfunction. Sweating may still be present → Call 119 immediately
- Heat exhaustion: Consciousness is usually clear, but may be accompanied by severe weakness, dizziness, and vomiting → Cool down immediately and seek medical attention if no improvement occurs.
- If heatstroke is suspected, begin cooling immediately after calling 119. The most dangerous time is waiting for an ambulance and doing nothing.
- Do not force water or drinks to an unconscious person
1. What is different?
Thermoregulation works by sweating and dissipating heat as heat of vaporization. Heat exhaustion occurs when fluid and electrolytes are lost while thermoregulation is still functioning, leading to reduced circulating volume. Heatstroke occurs when the regulatory system itself fails after exceeding its limits. A person with heat exhaustion is often drenched in sweat, whereas classic heatstroke often produces hot, dry skin.
However, this feature of “stopping sweating” should never be taken as a standard. In heatstroke that occurs during exercise or labor, it is common for sweat to remain. It is safer to base the decision on mental status.
Comparison
| Category | Heat exhaustion | Heatstroke |
|---|---|---|
| Mental status | Clear. Dizzy but able to talk | Confusion, gibberish, strange behavior, convulsions, unresponsiveness |
| Body temperature | Often above normal or below 40 degrees | Commonly above 40 degrees, but cannot be ruled out based on field measurements alone |
| Sweat | A lot of cold sweat | Sweating often stops and the skin is dry and hot (exertional heatstroke is an exception). |
| Skin | Pale and clammy | Red and hot |
| Pulse | Weak and fast | Often fast and strong |
| Course | Usually improves with shade, rest, and fluids | Medical emergency; delayed treatment can cause multiple-organ damage |
| Response | Rest, hydration, electrolytes | Begin cooling immediately after calling 119 |
When measuring body temperature, the armpit temperature is likely to be lower than the core body temperature. Measuring 39 degrees at the scene is not grounds for reassurance, and the exposure situation and systemic condition, especially neurological symptoms such as confusion, convulsions, and decreased response, must be considered together.
2. First aid procedure
2-1. Suspected heatstroke — a situation that requires order
- Call 119. If you notice any abnormalities in consciousness, call before taking any other step.
- Move to a cool place. Move out of direct sunlight to shade, an air-conditioned indoor space, or a cooled vehicle.
- Loosen your clothes and start cooling immediately. If possible and if the airway and condition can be continuously observed from the side, immersion in cold or ice water is the fastest cooling method. If immersion is difficult, spray cold water on your skin, move air across the skin with a hand fan or electric fan, and apply cold compresses to your neck, armpits, and groin.
- If they are unconscious, do not feed them anything. If liquid enters the airway when the swallowing reflex is impaired, it may lead to aspiration pneumonia or airway obstruction.
- Roll the person onto their side and keep the airway open. Because vomiting may occur, the recovery position (lying on one’s side) is safe.
- If not breathing, perform CPR. It is carried out under the guidance of the 119 dispatcher.
In principle, cooling should begin before the arrival of emergency services. In heatstroke, the prognosis is determined by the duration of high temperature, so every minute spent waiting without cooling matters.
2-2. Heat exhaustion
- Lie down in a cool place with your legs slightly higher than your heart.
- Loosen your clothes and cool off with a wet towel and air.
- Only if the person is fully alert, give small amounts of cool water or electrolyte drinks.
- If you do not get better within 30 minutes or are unable to drink water due to vomiting, go to a medical facility.
2-3. What not to do
- Wiping the body with alcohol — not recommended due to absorption and vascular response issues
- Caffeinated beverages or alcohol — their diuretic properties increase dehydration
- Take fever reducers — The high temperature of heatstroke has a different mechanism from infectious fever, so fever reducers do not work and only increase the burden on the liver and kidneys.
- Delay cooling — If possible, use cold or ice water immersion, but do not leave the patient alone and continue to monitor the airway and breathing. If immersion is difficult, start spraying and blowing cold water immediately.
3. Criteria for going to the hospital
- If there is any change in consciousness at all
- If the temperature is above 39 degrees and does not go down even after cooling
- If you are unable to drink water due to repeated vomiting
- If urine does not come out for more than 8 hours or is cola-colored (possibility of rhabdomyolysis)
- The standard is set lower for older adults, people with heart or kidney disease, and people taking diuretics, antidepressants, or anticholinergics.
4. What you see in the otolaryngology clinic in the summer
When indoor air conditioning is strong during hot weather, the mucous membranes of the nose and throat dry out rapidly. Additionally, as moisture is lost due to outdoor activities, mucus becomes sticky, increasing the number of people complaining of stuffy nose, foreign body sensation in the throat, and dry cough. Although it is not a problem that is directly related to heat-related illness, hydration is the underlying factor in both situations. This is why the habit of drinking before you feel thirsty and managing the humidity in an air-conditioned space are both helpful.
Frequently Asked Questions
Q. If I am sweating heavily, does that rule out heatstroke? A: No. The cessation of sweating is a characteristic of classic heatstroke, and sweating often remains in heatstroke caused by exercise or work in a hot environment. Use mental status—not the presence or absence of sweat—as the key warning sign.
Q. Is it necessary to drink isotonic beverages instead of water? A. For light activities lasting less than an hour, water is sufficient. If you sweat a lot or exercise for a long time, sodium loss increases, so electrolyte drinks are better. Drinking large amounts of water alone can cause hyponatremia.
Q. If a person with heatstroke regains consciousness, is it okay to not go to the hospital? A. Yes. Emergency medical evaluation is still required. Even if consciousness returns, damage to the kidneys, liver, and muscles may have progressed while the high temperature persists, and these changes may become apparent several hours to a day later. In principle, if there has been a decrease in consciousness, an evaluation is required.
This article is general health information and is not a substitute for individual medical care. If symptoms persist or worsen, please seek treatment at a medical institution.