He has been working in the courtyard since noon. It is 3 PM, the temperature is 43°C, and he has just walked inside and sat down heavily. His face is flushed red. He is sweating through his shirt. He says his head is pounding and the room feels like it is moving. He is 67 years old.
You have roughly ten minutes to make the right call.
Give him water and rest, and he will recover on his own within half an hour. Call 108 and start cooling him immediately, and you may save his life. Give him water when his body needs 108 — and you have made a dangerous mistake. The two conditions look almost identical from the outside. The difference between them is not a thermometer reading. It is one question you can ask him right now.
The One Test That Tells You Which Condition This Is
Ask him clearly: “What day is it? Where are we right now?”
If he answers correctly and his thinking seems normal — confused about nothing except how bad he feels — that is heat exhaustion. Serious, but manageable at home if treated immediately and correctly.
If he cannot answer, answers wrongly, seems disoriented about who or where he is, is slurring his words, or becomes aggressive or agitated without reason — that is heat stroke. Call 108 now. Do not wait for a thermometer. Do not give him water. Start cooling him immediately while the ambulance is on the way.
This mental state test is the single most practical tool you have in the first two minutes of a heat emergency. It does not require equipment. It does not require medical training. It requires only that you ask and listen carefully to the answer.
Quick Answer
Heat exhaustion: Temperature below 40°C, heavy sweating, dizziness, headache, nausea, muscle cramps — but mental state is normal. Treat at home: cool room or shade, oral fluids (water or ORS), fan, loosen clothing, rest. Reassess in 30 minutes. If not improving — escalate.
Heat stroke: Temperature at or above 40°C, mental confusion or altered behaviour, may stop sweating despite extreme heat. Life-threatening emergency. Call 108. Cool the person immediately with cold water on skin — especially neck, armpits, groin. Do not give anything by mouth if the person is confused or unconscious. “Cool first, transport second” — per National Centre for Disease Control (NCDC), Ministry of Health and Family Welfare, 2024 Emergency Cooling Guidelines.
How These Two Conditions Sit on the Same Spectrum
Heat-related illness is not two separate events that happen independently. It is a progression. The body is trying to manage a core temperature that is rising beyond its capacity to regulate.
It begins with heat cramps — painful muscle spasms, usually in the legs and abdomen, from the loss of salt through sweating. This is the earliest warning. Then it moves to heat exhaustion — the body is running out of the fluid and electrolyte reserves it needs to keep sweating and cooling itself. If heat exhaustion is not treated and the person stays in the heat, the cooling mechanism fails entirely, and core temperature climbs above 40°C into heat stroke territory. At that point the brain and organs are at risk.
This progression can happen within hours. In children, the elderly, and those with underlying conditions, it can happen faster. According to the National Disaster Management Authority (NDMA) guidelines on heat-related illness, heat stroke occurs when body temperature reaches 40°C (104°F) or above and is accompanied by delirium, seizures, or coma. Heat exhaustion, by contrast, typically presents with sweating, dizziness, and weakness — but mental state remains intact.
The reason this matters practically: the first aid for heat exhaustion includes giving oral fluids. The first aid for heat stroke explicitly does not — a confused or semi-conscious person given water to drink risks inhaling it into the lungs. The treatments diverge at exactly the point where the two conditions look most similar from the outside.
The Five Signs That Actually Tell Them Apart
Sign 1 — Mental State (Most Important)
Heat exhaustion: the person knows where they are, can answer questions coherently, and is aware of feeling unwell. They may be frightened. That is normal and a good sign — it means the brain is functioning. Heat stroke: disorientation, confusion, wrong answers, aggression, slurred speech, or loss of consciousness. Any change in mental state that cannot be explained by normal distress or pain is heat stroke until proven otherwise.
Sign 2 — Sweating Pattern
This is the observation that most consumer guides describe incorrectly. Heat exhaustion almost always involves heavy sweating — the body is working hard to cool itself and the mechanism is still functional. Heat stroke, particularly the classic non-exertional type common in elderly Indians sitting in hot rooms or direct sun, often presents with hot, dry skin because the sweating mechanism has shut down entirely. The skin is red, hot, and dry despite the extreme body temperature. This is a dangerous sign. When you touch the person’s skin and it feels extremely hot but is not sweating, treat it as heat stroke.
Exertional heat stroke — the type that occurs in construction workers, athletes, or outdoor labourers in intense physical activity — may still involve sweating. So the absence of sweat confirms heat stroke; the presence of sweat does not rule it out. Mental state remains the more reliable test.
Sign 3 — Body Temperature
Heat exhaustion: typically below 40°C. Heat stroke: 40°C or above. If you have a thermometer, this is a useful confirmation — but it is not a precondition for acting. Do not wait for a thermometer reading before deciding. Use the mental state test. If the thermometer is not available and the mental state test suggests heat stroke, treat for heat stroke.
Sign 4 — Pulse
Heat exhaustion tends to produce a fast but weak pulse — the heart is working harder to circulate blood and regulate temperature but is not yet overwhelmed. Heat stroke tends to produce a rapid and very strong pulse as the cardiovascular system goes into crisis. This distinction is less easy for a non-medical person to assess accurately under pressure; note it but do not rely on it as the primary differentiator.
Sign 5 — Rate of Deterioration
Heat exhaustion that is treated correctly — person moved to shade or AC, given water, fanned — shows improvement within 15 to 30 minutes. If the person’s condition is not improving or is worsening despite these measures, do not wait further. Call 108. Heat stroke deteriorates rapidly. Every 10 minutes at extreme body temperature increases the risk of organ damage and death.
Also Read: How to protect skin from summer sun exposure and UV damage
What the Indian Summer Does That Makes This More Dangerous Here
Most global medical content on heat illness is written for temperate climates where 35°C is an exceptional temperature. Across north-central India — Rajasthan, Madhya Pradesh, Uttar Pradesh, Bihar, Odisha, Andhra Pradesh, Telangana, and Maharashtra’s interior — 42 to 46°C in May is a routine weather pattern, not an emergency event. In 2024, 37 Indian cities recorded temperatures above 45°C between March and June, according to the India Meteorological Department data reported by Down to Earth (September 2024). Over 40,000 cases of heat stroke were officially recorded that season across the country.
The population most at risk in Indian conditions is not who most people assume. It is not only outdoor labourers and athletes. It is elderly people sitting in inadequately ventilated rooms, sleeping through midday heat in homes without fans or with power cuts, or doing light activity — watering plants, household repairs — during the 11 AM to 4 PM window when ambient temperatures peak. In 2024, election duty workers — government employees doing administrative work, not physical labour — died of heat stroke in Odisha and other states during phase-one polling in intense heat, as documented by HeatWatch’s September 2024 report. These were not people doing strenuous outdoor work. They were doing desk tasks in inadequately cooled conditions.
Children left in parked vehicles are a specific and severe risk that Indian families underestimate. A car parked in full May sun with windows closed reaches interior temperatures of 60 to 70°C within 15 to 20 minutes of the engine being off, even when the outside temperature is 40°C. A child’s body temperature rises three to five times faster than an adult’s. This is a heat stroke risk that materialises in minutes, not hours.
What to Do for Heat Exhaustion — the First 30 Minutes
Move the person immediately to the coolest available space — an air-conditioned room if possible, or a shaded, well-ventilated area under a ceiling fan. Remove outer clothing or loosen it. Have them lie down with their legs elevated slightly if they feel faint, to help blood flow return to the brain.
Give water or oral rehydration solution (ORS) — available at any chemist for under ₹10 per sachet — in small, steady sips. Do not give large quantities at once; it can cause vomiting. Do not give sugary drinks, carbonated drinks, tea, coffee, or alcohol. The NCDC’s 2024 public health advisory explicitly lists these as substances that increase fluid loss and worsen heat illness.
Fan the person or apply cool, damp cloths to the forehead, neck, and wrists. If you have access to a cold wet towel, place it on the back of the neck — the skin there has blood vessels close to the surface and cooling it helps reduce overall body temperature.
Watch the 30-minute mark. If the person has not shown meaningful improvement — if dizziness persists, if they cannot stand without assistance, if symptoms are worsening in any way — call 108. Heat exhaustion that does not respond to basic first aid within 30 minutes has either progressed to early heat stroke or has an underlying complication. Do not manage it at home any longer.
What to Do for Heat Stroke — Call 108 and Cool Simultaneously
The National Centre for Disease Control’s 2024 Emergency Cooling Guidelines for severe heat-related illness state the principle clearly: “cool first, transport second.” Waiting for the ambulance to arrive before beginning cooling wastes the most critical minutes. The recommended cooling rate is 1°C per 10 minutes, with the target being to bring body temperature below 39°C.
Call 108 first — say clearly that you have a suspected heat stroke case with confusion or unconsciousness, give your location, and stay on the line if instructed. Then immediately begin cooling while waiting.
Apply cold water to the person’s skin. The most effective areas for rapid cooling are the neck, armpits, and groin — where major blood vessels pass close to the skin surface. If you have ice available, wrap it in a cloth and apply it to these areas. If you have a cold wet bedsheet, wrap the person in it. Fan them vigorously to accelerate evaporative cooling. If a bathtub of cold water is accessible and the person is conscious, immersion in cold water is the fastest cooling method — this is what the NCDC’s 2024 emergency guidelines recommend for medical facilities and, where practical, as a first aid measure.
Do not give anything by mouth to a person who is confused, drowsy, or unconscious. The risk of aspiration — fluid entering the lungs — is real and can cause serious additional harm. Even if they ask for water, do not give it in this state. Focus on external cooling and keeping the airway clear while waiting for medical help.
If the person loses consciousness: place them in the recovery position — on their side with the top knee bent forward to prevent rolling, and the head tilted back slightly to keep the airway open. Do not leave them alone.
Two Indian Households — What Happened and Why
Suresh Khatri, 68, Nagpur. Retired government employee. His daughter-in-law found him sitting in the courtyard at 2:30 PM in late May — he had been doing light garden work and said he felt weak and dizzy. His shirt was soaked through. She asked him what he had eaten for lunch and he answered correctly. She checked — he was sweating heavily, his pulse felt fast but not alarming, and he was fully coherent. She recognised this as heat exhaustion. She helped him inside to the room with the cooler, made him lie on the floor which was cooler than the bed, gave him two glasses of water slowly over 20 minutes, and applied a damp cloth to his forehead and neck. By 3:15 PM, his headache had eased, he could walk without support, and he was able to eat a small meal. No hospital visit was needed. The key: she tested his mental state first and it was clear.
Rajan Mourya, 52, construction foreman, Delhi. His crew was pouring concrete in a rooftop project in June. One of his younger workers — 24 years old, previously healthy — stopped working and sat down suddenly at 1 PM. He seemed confused, could not say what project they were on, and when a colleague tried to help him up, he became briefly aggressive. His skin was warm but had stopped producing sweat despite the 44°C heat. Rajan called 108 immediately and directed his team to pour water from their cooler over the man’s arms, neck, and head while they waited. He stayed conscious but confused until the ambulance arrived 14 minutes later. He was hospitalised, treated with IV fluids and active cooling, and discharged after two days. The medical team told Rajan that the external cooling his team had started before the ambulance arrived had almost certainly prevented organ damage. He had not given the man anything to drink.
Six Mistakes That Cost Lives in Indian Heat Emergencies
❌ Giving water or ORS to someone who is confused or drowsy
✅ Give oral fluids only to someone who is fully conscious, can hold the glass themselves, and can swallow without difficulty. If there is any doubt about the person’s level of consciousness or ability to swallow safely, do not give anything by mouth. Aspiration in a heat stroke patient can cause aspiration pneumonia, adding a life-threatening complication to an already critical situation.
This happens because giving water feels like the right instinct — dehydration is part of the problem, and helping someone drink feels like direct action. But in heat stroke with altered consciousness, it is dangerous.
❌ Waiting to call 108 because “they just need to rest a bit”
✅ If there is any confusion in the person’s mental state — even mild disorientation, slow or wrong answers, unusual behaviour — call 108 immediately and begin cooling. Every minute at body temperature above 40°C increases the risk of brain and kidney damage. There is no version of heat stroke where waiting half an hour to see if they improve on their own is the right decision.
This happens because heat stroke often looks like “very bad heat exhaustion” rather than a distinct crisis, and Indian families are often reluctant to summon emergency services unless someone is clearly unconscious.
❌ Using only a damp cloth on the forehead and considering that adequate cooling for heat stroke
✅ A damp cloth on the forehead cools a small area of skin. For heat stroke, where body temperature needs to fall 1°C every 10 minutes, the most effective accessible interventions are cold water applied to the neck, armpits, and groin — and, if possible, partial or full immersion in cold water. The forehead cloth is not wrong — it is simply insufficient as the only cooling measure for a life-threatening temperature elevation.
This happens because the forehead-cloth image is deeply embedded in Indian household first aid memory from decades of treating fever.
❌ Leaving a child in a parked car “for five minutes” during Indian summer
✅ Interior car temperature in direct May sun at 42°C outside can reach 60 to 70°C within 15 minutes of the engine being turned off. A child’s core temperature rises three to five times faster than an adult’s. Five minutes in these conditions is enough to cause heat stroke in a young child. Take the child out of the car every time, without exception, regardless of how briefly you plan to be away.
This happens because parents underestimate how rapidly a parked car heats in Indian summer conditions and overestimate how quickly they will return.
❌ Trying to “break the fever” for heat stroke using paracetamol or other antipyretics
✅ Paracetamol and other fever-reducing medications work by resetting the brain’s internal thermostat. In fever, the thermostat is set too high. In heat stroke, the thermostat is not the problem — the body is overwhelmed by external heat and cannot cool itself physically. Paracetamol does nothing for heat stroke and may cause additional liver stress in someone already under severe physiological pressure. The treatment is physical cooling only — external cold water and shade — while getting the person to medical care.
This happens because high body temperature from any cause looks like fever, and the fever reflex is to give Calpol or Crocin.
❌ Assuming a young, healthy adult cannot get heat stroke
✅ Young, healthy adults — including fit men in their 20s and 30s — are fully vulnerable to heat stroke when exposed to prolonged extreme heat, especially combined with physical exertion, dehydration, or alcohol intake. The 2024 NCDC data showed heat stroke cases across all age groups in India, with outdoor workers under 40 representing a significant proportion of cases. Fitness does not protect against the physiology of heat overload; it only slightly delays the onset.
This happens because heat stroke is culturally associated with elderly people and children, making younger adults and their families dismissive of early warning signs.
Also Read: How to keep mosquitoes away while spending time outdoors during Indian summer
Frequently Asked Questions
What is the emergency number to call for heat stroke in India?
Call 108 — the National Ambulance Service, available in all states. When you call, state clearly that you have a suspected heat stroke patient with confusion or loss of consciousness and give your precise location. The 108 service can direct you on cooling measures to continue while the ambulance is in transit. In states where 108 coverage is limited or response times are long, the nearest government hospital emergency department is the fastest alternative. Do not drive the person yourself if they are unconscious or having seizures — you need a second person to monitor them in the back seat.
How long does it take to recover from heat exhaustion?
Most cases of heat exhaustion — caught before any mental state change occurs and treated correctly with cooling and oral fluids — show significant improvement within 15 to 30 minutes. Full recovery, meaning the person feels well enough to move around and resume light activity, typically takes a few hours to a full day. The NCDC advises that anyone who has experienced heat exhaustion should avoid returning to outdoor heat exposure for at least 24 hours. Returning to the same conditions too quickly, even after feeling better, can trigger a faster relapse because the body’s heat regulation system has already been stressed.
Can heat stroke happen even if someone has been drinking water regularly?
Yes. Hydration reduces the risk significantly but does not eliminate it. Heat stroke occurs when the body’s cooling system is overwhelmed by ambient temperature — particularly in elderly people during non-exertional exposure, such as sleeping in a hot room without a fan during a power cut. In these cases, the body cannot sweat enough to maintain temperature regardless of hydration status, especially when the external temperature is above body temperature for extended periods. Water intake is essential but is not the only factor.
Is ORS better than plain water during heat exhaustion?
ORS (oral rehydration solution) is marginally better than plain water because it replaces both fluid and the electrolytes — primarily sodium and potassium — lost through sweating. Heavy sweating depletes electrolytes, and plain water replacement without electrolytes can, in extreme cases, further dilute blood sodium and cause a condition called hyponatremia. In practice, for a household emergency, plain water is adequate and should not be withheld in favour of waiting for ORS. Give water immediately; ORS from a sachet can follow. ORS sachets cost under ₹10 per packet at any chemist. Coconut water is a reasonable natural alternative with adequate electrolyte content.
Can someone get heat stroke without first having heat exhaustion?
Yes. Classic heat stroke — the type that affects elderly people in hot rooms, or people with medical conditions that impair sweating — can develop without the preceding heat exhaustion phase. This is one of the more dangerous aspects of the condition, because there may be no warning period of dizziness and sweating before the person becomes confused. This is why checking on elderly family members during peak summer hours — particularly during power cuts — is important even when they appear to be resting comfortably. Altered behaviour or confusion in an elderly person on a hot day is a heat stroke signal until proven otherwise.
What should someone eat and drink in the hours after recovering from heat exhaustion?
Plain water and ORS first, in steady sips rather than large amounts. Once the person is fully alert and the dizziness has resolved, light foods that are easy to digest — rice, dal, curd, fruit — are appropriate. Avoid heavy meals, spicy food, alcohol, and caffeinated drinks for at least 24 hours. The digestive system is under stress after heat exhaustion, and heavy food diverts blood flow to digestion at a time when the body’s priority should be restoring temperature regulation and fluid balance. Continue monitoring for any return of dizziness or confusion through the rest of the day.
Are certain Indian summer conditions more dangerous than others?
High humidity combined with high temperature is more dangerous than dry heat alone. When ambient humidity is above 60 to 70%, sweat cannot evaporate efficiently — the cooling mechanism that prevents heat illness is impaired. Coastal cities like Mumbai, Chennai, and Kolkata in May–June experience this combination regularly. A temperature of 37°C at 80% humidity causes more physiological stress than 43°C at 20% humidity in Rajasthan. This is why NDMA’s advisories mention the heat index — the felt temperature accounting for humidity — rather than temperature alone. Check both the temperature and the humidity reading, not just the temperature, when assessing outdoor risk.
Can someone with a chronic condition — diabetes, heart disease, high blood pressure — take any specific precautions during Indian summer?
Yes, and this group needs specific attention. People with diabetes have impaired sweating response and reduced ability to detect early heat stress signals. People with heart disease or those on beta-blockers, diuretics, or ACE inhibitors have reduced cardiovascular reserve for heat stress, and diuretics increase fluid loss. People on antipsychotic medications or antihistamines have impaired sweating. None of these groups should be outside between 11 AM and 4 PM in Indian summer without shade and water. They should inform their doctor before summer begins about any medication adjustments needed during heatwave conditions. If in doubt about any medication’s interaction with heat stress, consult a general physician — this is a genuine clinical question, not a routine precaution.
Information last verified: May 9, 2026. Primary sources: National Disaster Management Authority (NDMA) Heat Wave guidelines at ndma.gov.in; National Centre for Disease Control (NCDC), Ministry of Health and Family Welfare — Emergency Cooling for Severe Heat-Related Illnesses, March 2024; NCDC Public Health Advisory: Extreme Heat/Heatwave 2024; India Meteorological Department (IMD) 2024 heatwave data as reported by Down to Earth, September 2024; HeatWatch Report — “Struck by Heat: A News Analysis of Heatstroke Deaths in India in 2024,” September 2024; Factly analysis of NDMA, NCRB and MOHFW heat death data, February 2025.
Emergency number for heat stroke in India: 108 (National Ambulance Service).
If any guideline or protocol referenced in this article has been updated since publication, write to editorial@tipsclear.com. This article is reviewed every 90 days during summer months.
Chinnagounder Thiruvenkatam is the Founder and Publisher of dailyhindnews.in/ and Tips Clear Media LLP, Chennai. A 25-year veteran of the CRPF, he has spent his publishing career since 2016 applying firsthand experience of Indian conditions to help Indian households make safer, better-informed practical decisions. Full author profile →
Disclaimer: This article provides general health information based on official Indian government guidelines and is for educational purposes only. It does not replace the advice of a qualified medical professional. In any suspected heat stroke emergency, call 108 immediately. Do not delay emergency medical care based on information in this or any other article.