Heat Exhaustion: What To Do Right Away

Key takeaways

Someone pouring sweat, with a headache, dizziness, cool pale skin, who is STILL AWAKE, answering properly and able to drink: that is heat exhaustion.
What to do straight away: stop what you are doing, get into the cool, loosen clothing, cool the skin with cool water and a fan, sip water. Do not leave the person alone.
Consciousness is the dividing line. Confusion, slurred or rambling speech, a seizure, not rousing when called means it has become heat stroke — call 115 and start cooling at once, and give nothing to drink.
According to CDC, heat exhaustion that is not dealt with can progress to heat stroke; seek medical attention if symptoms get worse or last longer than an hour.
Do NOT give alcohol or coffee, do NOT give salt tablets, do NOT give fever medicine, do NOT rub alcohol on the skin, and do NOT drive yourself to hospital.

On a hot day someone working outdoors suddenly has a headache, feels dizzy, is soaked in sweat, and their skin turns cool and pale — but they are still awake, still answering properly and still able to drink. That is heat exhaustion. The work at home is very concrete, and there is one thing you have to keep watching throughout.

Recognising it: the signs of heat exhaustion

According to CDC, the signs include:

Heavy sweating; skin that is cool, moist and pale.
Headache, dizziness, light-headedness on standing, sometimes fainting.
Feeling drained, weak, irritable.
Great thirst; passing less urine than usual, and darker.
Nausea or vomiting.
Cramps or spasms in the abdomen, the arms or the legs.
A fast but weak pulse, fast shallow breathing.

The thing that wrongly reassures a family: the person themselves waves it off. According to CDC, people with severe heat-related illness do not always recognise how much danger they are in — do not let them decide for themselves that they will rest a moment and then carry on.

What to keep watching: consciousness

Heat exhaustion	Heat stroke
Still awake, answering properly, able to drink	Confused, rambling speech, seizure, not rousing when called
Pouring sweat, skin cool and pale, clammy	Skin hot and red, may be dry or still moist

This is a scale, not two separate illnesses: according to CDC, heat exhaustion that is not dealt with can progress to heat stroke, and a change in consciousness is a sign of heat stroke and calls for action at once. The moment consciousness changes, it has become heat stroke, and from then on it is an emergency.

What to do straight away

STOP what you are doing; do not finish the job first.
GET INTO THE COOL: shade, a room with a fan or air conditioning. Sit or lie the person down with both legs raised.
LOOSEN AND REMOVE unnecessary clothing, shoes and socks included.
COOL THE SKIN: spray or sponge the body with cool water and then fan it; put cool cloths on the neck, the armpits and the groin, changing them constantly.
GIVE DRINKS, only if the person is fully awake and not vomiting: sips of cool water.
STAY WITH THEM: according to CDC, do not leave the person alone until they have received medical care.

According to CDC, water is enough in most cases; when sweating heavily for a long time, use a drink containing electrolytes, mixed with exactly the amount of water stated on the packet. CDC also notes avoiding water that is too cold, because it can cause stomach cramps.

What must NOT be done

Do NOT give drinks containing alcohol or caffeine — MedlinePlus lists both among the things not to do. CDC says alcohol and very sugary drinks cause the body to lose more fluid.
Do NOT give salt tablets, and do not mix up your own salt water from a tip someone passed on. According to CDC, avoid salt tablets; drinks containing electrolytes are fine.
Do NOT give fever medicine. MedlinePlus states plainly that aspirin and paracetamol (acetaminophen) are not to be used in a heat emergency: this heat comes from the surroundings, not from a fever.
Do NOT rub alcohol or spirits on the skin — MedlinePlus also lists this among the things not to do.

Do NOT put anything in the mouth of someone who is vomiting or not fully awake — that is already the border of heat stroke.
Do NOT go back to work or finish the training session. According to CDC, feeling tired while working in the heat is a serious warning, and heat exhaustion can progress quickly to heat stroke if it is not dealt with.
Do NOT drive yourself to hospital — NHS says this explicitly.

When you must go to hospital

CALL 115 (the emergency number in Vietnam) or go to emergency care NOW if, during or after being out in the heat, there is ANY of the following: confusion, rambling speech, slurred speech, behaving unlike themselves · hard to rouse, unconscious, having fainted · a seizure · skin hot and red and sweating has stopped · vomiting repeatedly, unable to keep a single sip of water down · fast breathing, difficulty breathing, a very fast pulse · already in the cool, already rested, already given water and still no better · urine the brown of strong tea after exertion in the heat. — BE SEEN THE SAME DAY, do not leave it until tomorrow, if: the episode has passed but a lot of tiredness, headache, dizziness or nausea remains · urine is still scant and dark despite drinking · cramps will not stop, or the person has heart disease or is on a prescribed low-salt diet. Keep the threshold for waiting far lower for anyone aged 65 or over, anyone pregnant, and anyone with heart disease, kidney disease, diabetes or asthma, or taking diuretics; take newborns and small children to a medical facility rather than managing at home.

CDC places urine the brown of strong tea in the group that needs medical care immediately, with blood tests done at a medical facility.

Prevention is cheaper than treatment. According to CDC, drink more water whether or not you are being active, and do not wait until you are thirsty; anyone on a fluid restriction or taking diuretics should ask their doctor. Rest in the shade in blocks, and move heavy work to the cooler part of the day; anyone new to working in the heat, or just back after a break, should build up gradually. CDC also advises working in pairs, with two people watching each other for the signs.

At home you can do the cooling, the fluids and the watching, but you cannot measure how dehydrated someone is. Y Te Xanh (GreenCare) comes in at the two ends on either side of that: a remote consultation by video call when you are unsure whether you need to go in; then a doctor coming to the house to take the history, examine, measure the vital signs and say clearly which cases must be admitted; and a nurse for recovery care at home afterwards. With a sign in the box above, go in first and call afterwards — a remote consultation is not for someone drowsy or having seizures.

This article passes on the recommendations of public health authorities — sources: the US CDC including NIOSH; NHS in England for the markers to watch and the point about not driving yourself; and MedlinePlus at the US National Library of Medicine for the things that must not be done — and does not replace being examined in person. Citing CDC here does not imply that CDC endorses Y Te Xanh or our services.

Need personalised advice for your loved one? Call our hotline 094 368 81 15 (24/7) — calling to ask a question or to book costs nothing. GreenCare has doctors who come to examine, nurses who carry out doctor's orders (injections, infusions, dressing changes), remote consultation by video call, and a review of the medicines you are taking; an in-depth remote consultation, or any one after the first, is a paid service. For children we take examination and acute care only — not long-term care at home, and not newborns or expectant mothers. We confirm we have staff in your area and provide transparent pricing before we begin.

Sources

Frequently asked questions

Is heat exhaustion the same as sunstroke?

In everyday Vietnamese the two names are used almost interchangeably, and both usually point at the same thing: heat exhaustion. “Sunstroke” sounds as though the sun has to be shining on you, but according to CDC heat illness comes from exertion or from a hot environment — a closed workshop or an airless house will do it too, so “heat illness” describes it better. What matters is not which name you use but which level the person is at: still awake and able to drink means dealing with it at home and then watching; already confused, rambling or not rousing means heat stroke and calling 115 — this site has a separate article on heat stroke that covers the cooling in detail.

How long without improvement means something is wrong?

According to NHS, someone with heat exhaustion usually feels better within about 30 minutes if they are brought into the cool, cooled down and given water to drink. NHS places still feeling unwell after half an hour of resting in the cool, being cooled and drinking water in the group that means calling the emergency services. According to CDC, seek medical attention if symptoms get worse or last longer than an hour; MedlinePlus likewise says to call for emergency help if the condition worsens despite treatment. Do not sit and count the clock: if it gets worse at any point, go; and if consciousness changes, call 115 at once.

Can oral rehydration solution be given?

Yes, if the person is fully awake and not vomiting. According to CDC, water is enough in most cases, and when sweating heavily for a long time a drink containing electrolytes makes more sense; NHS names an isotonic sports drink as one option in this situation. If you use a rehydration sachet, mix it with exactly the amount of water on the packet and give it in sips; do not make it stronger than the instructions, do not split a sachet, and do not mix up your own salt water from a tip someone passed on. Anyone vomiting or not fully awake is given nothing by mouth — MedlinePlus states that plainly.

Should they go straight into a cold shower to cool down?

Cooling the skin with cool water is the RIGHT thing to do: NHS says to spray or sponge the person with cool water and then fan them, MedlinePlus says to apply cool wet cloths or pour cool water on the skin and then fan, and CDC says to cool with water, cool cloths or a fan. None of those documents says to avoid cool water; what is forbidden is rubbing alcohol or spirits on the skin. There is only one practical caution: someone who is dizzy or light-headed should not be left to go into the bathroom alone, because they may faint — sitting or lying them down in the cool and then sponging, spraying and fanning is enough, and always with someone beside them.

Can they go back to work the next day?

The documents above do not set a fixed number of days for returning to work — that is for a doctor to decide case by case, particularly for someone with heart disease, kidney disease or diabetes, or taking diuretics. What CDC does say is this: anyone new to working in the heat, or just back after a period away, needs to build up gradually and should not take on the same workload immediately. While the tiredness lasts, avoid heavy work and the hottest part of the day; and if a lot of tiredness, a headache or dark urine persists, be seen before going back to work.

How should heat cramps be dealt with?

According to MedlinePlus, give water or a drink containing electrolytes as above, then massage the cramping muscle gently but firmly. According to CDC, avoid salt tablets; drinks containing electrolytes are fine. CDC also says cramps, pain or spasms in the abdomen, the arms or the legs — whether they stand alone or come with other symptoms — should not be dismissed, because they can be the start of something more serious. Be seen if the cramps will not stop, or if the person has heart disease or is on a prescribed low-salt diet.