Heat stroke kills quietly — the warning signs are clear

On a 44°C afternoon, a little tiredness and thirst feel normal. But there is a line where the body stops coping — and crossing it quietly is what makes heat stroke so dangerous. The good news: the warning signs are clear, and acting early almost always works.

Most heat illness starts mild and is easy to reverse. It becomes an emergency only when the body's cooling system fails and core temperature climbs toward 40°C (104°F). At that point it stops being about comfort and becomes about the brain and organs.

• Early signs are your friend — heavy sweating, cramps, headache, weakness and dizziness mean: stop, get to shade, drink fluids now.
• Danger signs mean hospital, now — confusion, fainting, repeated vomiting, or hot dry skin that has stopped sweating. Do not wait it out.
• Some people tip over faster — the elderly, young children, outdoor workers, and anyone on certain medicines feel it less and lose water faster.
• Almost all of it is preventable — water, shade, timing and a close eye on the vulnerable do most of the work.

This is general information, not medical advice. If someone shows the danger signs, treat it as the emergency it is and get medical help fast.

Your body likes to stay near 37°C. When it heats up, it has one main cooling trick: pushing blood to the skin and making sweat, which carries heat away as it evaporates. On a hot day this works beautifully — until two things break it.

First, dehydration. Sweat is mostly water and salts. If you don't replace what you lose, there isn't enough fluid left to make sweat or pump blood to the skin. Cooling slows down, and core temperature starts to climb.

Second, humidity. Sweat only cools you when it evaporates. In muggy air it just drips, so even a soaked shirt is barely cooling you — which is why a humid 38°C can be deadlier than a dry 44°C.

When cooling fails badly, the body crosses into heat stroke: core temperature races past 40°C, and at that heat the brain and organs start to struggle. A frightening late sign is skin that turns hot and dry because sweating has shut down entirely.

Some people reach that line much sooner. Older adults feel thirst and heat less and sweat less. Small children heat up fast and can't tell you they're in trouble. Outdoor workers face hours of direct sun. And some common medicines — for blood pressure or water retention — reduce sweating or push out fluid, quietly stealing the body's defences.

Prevention is mostly small habits done daily. And if someone does go down, the first ten minutes of cooling matter more than anything else.

Heat stroke is a medical emergency — never try to 'sleep it off'. When in doubt, treat it as serious and get help.

Myth 1 — Only labourers and outdoor workers get heat stroke.

They are at high risk, but so are the elderly in a hot, unventilated room, children in a parked car, and gym-goers pushing hard in the heat. It can strike indoors too, with no sun at all — it's about the body's temperature, not just sunlight.

Myth 2 — Cold water or AC right after the sun is dangerous and causes 'loo'.

This is folklore. Cooling the body is exactly what you want. Cool (not ice-cold) water, a cool room and AC all help you recover — a fix, not a cause.

Myth 3 — If you're thirsty, you'll know in time to drink.

Thirst is a late signal — by the time you feel it, you're already a bit dehydrated, and in the elderly thirst is even weaker. Sip through the day, before thirst arrives.

Myth 4 — A glass of lassi, beer or a cold drink cools you down well.

Plain water, ORS, nimbu pani and chaas are the real rehydrators. Alcohol actually makes you lose more water, and sugary cold drinks aren't a good substitute for fluids and salts in real heat.

Myth 5 — Heat stroke just means feeling very hot and tired.

That's mild heat exhaustion. True heat stroke involves confusion, fainting, or hot dry skin and is a medical emergency. Knowing the difference is the whole point — one needs rest and fluids, the other needs a hospital.

Heat stroke is mostly diagnosed by what you see, not by a lab. There is no test you run at home, and for mild heat tiredness you usually need none at all. Costs below are rough India ranges and vary by city, lab and offers.

The one number worth memorising

• 40°C / 104°F core temperature is the threshold where heat exhaustion tips into heat stroke. Combined with confusion, fainting or hot dry skin, that means hospital — now.

When a hospital does run tests

• Electrolytes (sodium, potassium)to see how much salt and fluid the body has lost; part of a basic metabolic panel, often roughly ₹400–900.
• Kidney function (urea, creatinine)severe heat illness can strain the kidneys, so doctors check them; commonly ₹300–700, frequently bundled into a package.
• Other checks — like a CBC or muscle markers — may be added in serious cases. The doctor decides; you don't order these yourself.

Numbers worth knowing at home

• No test, just fluids is the right answer for mild cases — water and ORS, not a lab.
• ORS sachets cost only a few rupees and are the cheapest, most effective tool in the heat; keep some at home.

The smartest move isn't tracking lab values. It's recognising the danger signs early and getting medical help fast — in heat stroke, minutes matter far more than numbers.

Step back, and heat is one of the most underrated health risks of the Indian summer — not because it is mysterious, but because it is so familiar that we stop respecting it. Summers are getting hotter and heatwaves longer, which means more days each year when the body is pushed close to its limit. The lesson is not to fear the sun; it is to understand how heat works and build a few steady habits around it.

What makes this story hopeful is how much sits in ordinary hands. Almost every serious heat illness is preventable with water, shade, timing, and a watchful eye on the people most at risk. None of it needs money or machines — just attention. A bottle of water, a window curtain, a packet of ORS and a phone call to check on a grandparent do more than any gadget.

The deeper point is agency over panic. Heat stroke can be frightening, but it announces itself with clear signs, and the right response is simple and learnable: cool the body, give fluids, and get help when the danger signs show. Knowing that turns a scary word like 'loo' into something you can actually manage.

So let the season shape a calm routine rather than a fear. Drink before you're thirsty, dodge the worst hours, keep an eye on the vulnerable, and remember the one number — 40°C — that means it's time for a hospital, not a wait.