What is the difference between heat exhaustion and heat stroke?

Heat exhaustion means your body is struggling but still coping: heavy sweating, weakness, nausea, headache, and muscle cramps. Heat stroke means the body's cooling system has failed: skin becomes hot and often dry, the person is confused, stumbling, slurring words, or collapses. Heat stroke is a life-threatening emergency in Vietnam — call 115 immediately and cool the person aggressively while you wait.

How hot does Da Nang get in summer?

From April to August, Da Nang regularly reaches 35 to 40°C. The real danger is humidity: with humidity of 70 to 80 percent, a 37°C afternoon can feel like 45°C or more, because sweat evaporates poorly and your body cannot cool itself efficiently. The heat index, not the thermometer, is what makes travellers ill.

What should I drink for heat exhaustion in Vietnam?

Oral rehydration solutions and electrolyte drinks, not plain water alone. Every Vietnamese pharmacy sells Oresol (oral rehydration salts) for a few thousand dong, and convenience stores stock Revive and Pocari Sweat. Drink small, frequent sips — a large volume gulped at once often triggers vomiting in someone who is heat-stressed.

Can I get an IV drip for dehydration at my hotel in Da Nang?

Yes. If vomiting stops you from keeping fluids down, a licensed doctor from Viet Home Doctor can come to your hotel or apartment in Da Nang or Hoi An and give IV fluids with electrolytes, plus anti-nausea medication. Most patients feel dramatically better within one to two hours, and you get English documentation for travel insurance.

Is it safe to climb the Marble Mountains in the summer heat?

Yes, if you go early. The climb involves hundreds of stone steps with limited shade, and the caves trap humid air. Go at opening time (around 7:00), carry at least one litre of water per person, wear a hat, and avoid the 10:00 to 16:00 window from April to August. Midday Marble Mountains visits are one of the most common causes of tourist heat exhaustion we treat.

How much water should I drink per day in Da Nang's hot season?

Plan on at least 3 litres per day if you are outdoors, and more if you are hiking, golfing, or running. Add electrolytes — Oresol, Revive, or Pocari Sweat — rather than relying on plain water only, because heavy sweating drains sodium and potassium, and replacing water without salts can leave you weak, crampy, and nauseated.

Heat Exhaustion in Da Nang: Symptoms, Treatment & Prevention

Why Da Nang's Heat Catches Travellers Off Guard

Between April and August, daytime temperatures in Da Nang sit between 35°C and 40°C. That number alone doesn't sound extreme if you've holidayed in Spain or Australia. The problem is humidity. Coastal central Vietnam routinely runs at 70–80% humidity, which means the heat index — what the conditions actually do to your body — can be well above 45°C on a 37°C afternoon.

Humidity matters because your body cools itself by evaporating sweat. When the air is already saturated with moisture, sweat drips off you instead of evaporating, and your core temperature keeps climbing even while you feel soaked. Travellers arriving from cooler or drier climates have little heat acclimatisation, and the first two or three days of a trip are exactly when most heat illness happens.

Add a beach holiday's usual habits — long walks in direct sun, a couple of beers at lunch, forgetting to drink water — and you have the most common preventable illness we see in tourists every summer, second only to food poisoning.

Heat Exhaustion vs Heat Stroke: Know the Difference

These are two points on the same spectrum, and telling them apart quickly can save a life.

Heat exhaustion means your body is under serious strain but its cooling system is still working. Typical signs:

Heavy sweating — skin is pale, cool, and clammy
Weakness, dizziness, or feeling faint when standing up
Nausea, sometimes vomiting
Throbbing headache
Muscle cramps in the legs or abdomen
Fast, weak pulse; dark yellow urine or not urinating much

Heat exhaustion is treatable on the spot. If you act quickly, most people recover within a few hours.

Heat stroke means the cooling system has failed and core temperature is rising unchecked, cooking the brain and organs. The signs are different in kind, not just degree:

Skin turns hot and often dry — sweating may stop entirely
Confusion, disorientation, slurred speech, irrational behaviour
Staggering, seizures, loss of consciousness, collapse
Core temperature of 40°C or above

Heat stroke kills, and it kills fast. It is a 115 emergency. Do not try to manage it with water and rest, and do not put the person in a taxi hoping for the best without first cooling them. Call the ambulance, then cool aggressively while you wait: shade or AC, clothes off, water poured over the skin, vigorous fanning, ice or cold wet towels on the neck, armpits, and groin. Aggressive cooling before the ambulance arrives is the single biggest factor in survival.

The simplest field test: if the person is confused, or their skin is hot and dry, treat it as heat stroke. When in doubt, call 115.

Who Gets Caught Out

After several summers treating heat illness across Da Nang and Hoi An, the pattern is remarkably consistent:

Midday Marble Mountains climbers. Hundreds of steep stone steps, little shade, and caves full of trapped humid air. Visitors arrive at noon, underestimate the climb, and run out of water halfway up. Go at 7:00 instead.
My Khe beach walkers. The sea breeze feels cooling, so people walk the sand for an hour at 13:00 without noticing their body overheating. Sand also reflects heat upward.
Golfers. Four to five hours of sun exposure on courses like BRG and Montgomerie Links, often with alcohol. Golfers are heavily represented among our IV rehydration callouts.
Runners. Anyone keeping their home training schedule at Da Nang's pace. If you must run, do it before 6:30, cut your usual distance for the first week, and carry electrolytes.
Children in strollers. A covered stroller traps heat like a tent, and small bodies overheat far faster than adults. A child who becomes unusually quiet, flushed, or floppy in the heat needs immediate cooling and medical assessment.
Older travellers. Over 65, the body's thirst signal and cooling response are both weaker, and common medications (diuretics, blood pressure tablets, some antidepressants) make heat regulation worse. Symptoms can also be subtler — sometimes just fatigue and confusion.
Jungle trekkers. The approach hike is where heat exhaustion on an adventure trip actually happens — not underground, where caves are cool, but on the humid, unshaded walk in and out with a pack on. See our guide to caving and trekking injuries for the rest of what goes wrong on those days.

How to Treat Heat Exhaustion

Act at the first symptoms — don't push on to "finish the walk." The sequence:

Stop and get out of the heat. Air conditioning is best (a cafe, your hotel room, a Circle K); deep shade is second best. Lie down with legs slightly raised.
Loosen or remove excess clothing.
Rehydrate with electrolytes, in small frequent sips. This is the step people get wrong. Every pharmacy (nha thuoc) in Vietnam sells Oresol — oral rehydration salts you mix with bottled water — for a few thousand dong. Convenience stores everywhere stock Revive and Pocari Sweat. Sip small amounts of fluids every 10–15 minutes. Gulping half a litre at once frequently triggers vomiting in a heat-stressed stomach, which sets you back badly.
Cool the skin. A cool (not ice-cold) shower works well once you're back at your accommodation. Otherwise, wet towels on the neck and wrists and a fan.
Rest and monitor for 30–60 minutes. You should feel steadily better. No alcohol for the rest of the day, and stay out of the sun until tomorrow.

Escalate if symptoms are not clearly improving within an hour, if vomiting continues, or if any confusion appears — the last one means 115 immediately.

When You Can't Keep Fluids Down: IV Rehydration

The stubborn version of heat exhaustion looks like this: you're weak, your head is pounding, you know you need to drink — but every few sips come straight back up. Oral rehydration has failed, and each hour of vomiting digs the dehydration hole deeper.

This is exactly what IV fluid therapy at your hotel is for. A licensed Viet Home Doctor physician comes to your room in Da Nang or Hoi An with a litre or more of electrolyte fluids, anti-nausea medication, and monitoring equipment. Fluids go directly into the bloodstream, bypassing the rebelling stomach, and most patients go from miserable to functional within one to two hours — without spending the night in an emergency department waiting area. You'll also get an English medical report and itemised receipt for your travel insurance claim.

To be clear about the boundary: home IV therapy is for heat exhaustion with failed oral rehydration. Suspected heat stroke — confusion, hot dry skin, collapse — goes to hospital by ambulance, every time.

Prevention: How Locals Survive the Summer

Notice what Da Nang residents do: the beach is packed at 5:30 in the morning and again after 16:30, and nearly empty in between. Copy that rhythm.

Avoid direct sun between 10:00 and 16:00 from April through August. Schedule Marble Mountains, Son Tra rides, and long walks for early morning; spend midday in AC, museums, cafes, or the pool.
Drink 3 litres or more on outdoor days. Thirst lags behind need in humid heat. Check your urine: pale yellow is right, dark yellow means you're behind.
Electrolytes, not just water. Heavy sweating loses sodium and potassium. Replacing sweat with plain water alone dilutes what's left and can leave you weak, crampy, and nauseated despite "drinking plenty." One Oresol sachet or bottle of Pocari/Revive per few litres of water fixes this cheaply.
Limit alcohol and caffeine during the day. Both are diuretics; beach beers at noon are a classic setup for a 15:00 collapse.
Hat, light loose clothing, and real breaks. Sit in shade for 10 minutes every hour of exertion.
Give yourself 2–3 easy days when you arrive. Acclimatisation is real; your sweat response measurably improves over the first week.

A Word About Hoi An

Half an hour south of Da Nang, Hoi An deserves its own warning. The Ancient Town has very little shade: it's a grid of narrow streets between heat-absorbing yellow walls, largely treeless, and closed to cars — so you explore it entirely on foot. Add lantern-lit evening crowds that convince people the town is "a walking destination" at all hours, and midday visitors get hit hard. In summer the streets can feel like a slow oven from late morning onward.

The same rules apply, with extra force: explore at 7:00–9:30 or after 16:30, duck into cafes often, carry water plus electrolytes, and take the middle of the day at your hotel pool or in an air-conditioned tailor's shop rather than on the street. Cycling to the rice paddies or An Bang beach is lovely — before 9:00, not at 13:00.

Viet Home Doctor makes house calls in Hoi An as well as Da Nang, including IV rehydration at Ancient Town hotels and homestays, so the advice above doesn't change when you change towns.

The Bottom Line

Heat exhaustion in Da Nang is common, predictable, and almost entirely preventable: respect the 10:00–16:00 window, drink electrolytes rather than water alone, and act at the first symptoms instead of pushing through. Know the one distinction that matters — sweating, weak, and nauseated means treat and rest; hot, dry, and confused means call 115. For everything in between, including vomiting that defeats oral rehydration, an English-speaking doctor can be at your hotel in Da Nang or Hoi An within 1 hour. More traveller health guides are collected here.

Heat Exhaustion & Heat Stroke in Da Nang