Excessive Heat Health Effects: What Pakistanis Must Know

Every summer, millions of Pakistanis step outside into temperatures that their bodies were simply not built to handle. Excessive heat is not just about feeling uncomfortable or sweaty — it is a genuine medical emergency that has already claimed hundreds of lives across Pakistan, and the numbers are getting worse every single year.

In June 2024, over 568 people died in just six days during a single heatwave in Southern Pakistan. And that is just the official count. Doctors and health researchers believe the real number is far higher, because most deaths were recorded under labels like "cardiac arrest" or "organ failure" — not heat. The killer was invisible in the data, but very real on the ground.

This article is for every Pakistani who wants to understand what excessive heat actually does to the human body, who is most at risk, and — most importantly — what you can do right now to protect yourself and the people you love.

Excessive Heat and the Human Body — A Dangerous Combination

Your body is smarter than you think. When temperatures rise, it automatically starts working to cool itself down. Blood moves closer to the skin surface. Sweat glands activate. You breathe faster. This is your body doing everything it can to keep your core temperature from climbing too high.

But here is the problem: this cooling system has limits. When outdoor temperatures hit 45°C — which is now a regular occurrence in cities like Karachi, Jacobabad, and Dera Ismail Khan — and there are 10 to 12 hours of loadshedding on top of that, the body simply cannot keep up. The internal cooling mechanism breaks down. And when it does, things go wrong very fast.

The 4 Stages of Heat-Related Illness

Heat does not attack you all at once. It moves in stages, and most people in Pakistan make the mistake of ignoring the early signs until it becomes a crisis.

Stage 1 — Heat Rash: Small, red, itchy bumps on the skin. Usually on the neck, chest, or under the arms. This is your skin telling you the sweat glands are getting blocked. It looks minor but it is your body's first warning.

Stage 2 — Heat Cramps: Painful muscle spasms, usually in the legs or abdomen. This happens because excessive sweating drains your body of salt and fluids. Construction workers and farmers in Pakistan experience this almost daily during summer months but rarely take it seriously.

Stage 3 — Heat Exhaustion: This is where it gets dangerous. Heavy sweating, dizziness, nausea, weakness, rapid heartbeat, and a feeling that you might faint. Your body is struggling hard at this stage. If you do not act now, you move to the final stage.

Stage 4 — Heat Stroke: This is a medical emergency. Body temperature crosses 40°C. Sweating stops completely. Skin becomes hot and dry. The person may become confused, lose the ability to speak clearly, or lose consciousness altogether. Without immediate medical attention, heat stroke can cause permanent brain damage or death within hours.

Most Pakistani families do not know the difference between heat exhaustion and heat stroke. That gap in knowledge costs lives every summer.

What Heat Stroke Actually Does Inside Your Body

When your core body temperature rises above 40°C and stays there, your organs begin to suffer damage. This is not a metaphor — it is a biological fact.

The kidneys, which are already under stress in Pakistan's water-scarce regions, are among the first to be affected. Severe dehydration causes the blood to thicken, making the kidneys work harder to filter it. Eventually they can fail. Doctors in Karachi reported a surge in acute kidney injury cases during the 2024 heatwave that had nothing to do with infection or disease — it was purely heat-driven.

The heart faces a similar burden. As the body tries to push blood to the skin surface for cooling, the heart has to beat faster and harder. For people who already have high blood pressure, diabetes, or any cardiovascular condition, this extra strain can trigger a heart attack. This is why heat stroke deaths are often recorded as cardiac events. The connection is real, but it gets lost in paperwork.

The brain is not spared either. Neurological symptoms — confusion, slurred speech, inability to recognize family members — can appear within minutes of heat stroke. In severe cases, swelling in the brain leads to seizures or permanent cognitive damage. Children and elderly people are especially vulnerable to this.

Who Is Most at Risk From Excessive Heat in Pakistan?

Not everyone is equally vulnerable. Understanding who faces the highest risk helps families prioritize care and attention during heatwave season.

Children and Infants

Small children cannot tell you they are overheating. They do not sweat as efficiently as adults. Their bodies absorb heat from the environment much faster. Research has shown that each additional degree rise in minimum nighttime temperature above 23.9°C increases the risk of infant mortality by up to 22.4%. Think about what that means in a city like Karachi, where night temperatures in 2024 stayed above 32°C for days straight, and millions of families had no electricity for fans.

School timings in May and June are another serious concern. Children walking to school or sitting in classrooms without ceiling fans or any ventilation are being silently harmed. Cognitive function drops in extreme heat. Children cannot concentrate, retain information, or think clearly — and parents often mistake this for laziness or lack of interest.

Pregnant Women

This is a group that Pakistan's official heatwave guidelines have largely ignored — and that silence has consequences.

Pregnancy already changes the way a woman's body handles temperature. Hormonal shifts, increased blood volume, and carrying extra weight all make it harder to stay cool. When you add 45°C summers, loadshedding, and water shortages to that picture, the risks become serious. Research links excessive heat exposure during pregnancy to gestational diabetes, preterm birth, high blood pressure, and in some cases, stillbirth.

Women in rural Sindh face a particularly cruel reality. Water scarcity means they walk long distances carrying heavy loads — even during pregnancy — just to meet their household needs. The government's national heatwave guidelines mention checking on the elderly and children, but do not specifically address pregnant women at all. This is a gap that urgently needs to be filled.

The Elderly

Older adults are vulnerable for several reasons that compound each other. Their sense of thirst weakens with age, so they often do not drink enough water even when they are seriously dehydrated. Many take medications for heart conditions, blood pressure, or diabetes that interfere with the body's ability to regulate temperature. They are also more likely to live alone, meaning no one notices the early signs of heat illness until it is already critical.

Outdoor Workers and Daily Wage Laborers

Pakistan's informal economy runs on people who work outdoors — construction laborers, rickshaw drivers, roadside vendors, brick kiln workers, farmers. These workers have no choice. They cannot take a sick day. They cannot afford to lose a day's wage. So they stand in the sun for 8 to 10 hours at temperatures that would send anyone to a hospital, drink whatever they can find, and hope they make it home.

These are the people most likely to die during a heatwave, and they are also the ones least likely to be counted in official statistics.

Pakistan's Heatwave Reality-The Numbers Behind the Crisis

The 2024 heatwave was not a one-time disaster. It was a confirmation of a pattern that climate scientists have been warning about for years.

Temperatures in Karachi reached 47.2°C in June 2024. Twelve-hour power cuts made homes into heat traps. Hospital emergency rooms were overwhelmed. Morgues ran out of space. Over 568 official deaths were recorded in just six days — but researchers found that over 95% of heat-related fatalities were listed under other causes like dehydration-induced organ failure. The real death toll was almost certainly much higher.

What makes Pakistan particularly exposed is not just the temperatures. It is the combination of factors that hit all at once: extreme heat plus loadshedding plus limited access to clean drinking water plus strained healthcare infrastructure plus a large population working outdoors with no protection. Any one of these problems would be manageable. All of them together, in 47-degree heat, is a public health crisis.

And the trend is moving in the wrong direction. The frequency of heatwaves in Pakistan has increased fivefold over the past three decades. Regions that used to be spared — mountainous parts of Khyber Pakhtunkhwa — are now seeing annual extreme heat events. Cities are getting hotter as concrete replaces green cover. Since 2000, Karachi has lost nearly 80% of its green cover to development.

How to Protect Yourself and Your Family-Practical Steps That Actually Work

Knowing the risks is only useful if you also know what to do about them. Here are clear, practical steps grounded in what actually works in Pakistan's conditions.

At Home

Drink water before you feel thirsty. By the time your body signals thirst, you are already mildly dehydrated. During a heatwave, aim for at least 3 to 4 litres of water per day. If you are working outdoors or doing physical activity, you need even more.

Keep ORS (Oral Rehydration Solution) packets at home — these are inexpensive and available at any pharmacy. They replace both fluids and electrolytes lost through sweating, which plain water alone does not fully do.

If you have no air conditioning, wet towels on windows help reduce indoor temperature slightly. Sleep on lower floors — heat rises and upper floors can be several degrees hotter at night. Spray water on your wrists, neck, and forehead; these pulse points help cool blood temperature faster.

Avoid heavy, oily, or very spicy food during peak summer heat. Large meals raise your body's internal temperature as digestion takes energy. Eat smaller, lighter meals more often. Watermelon, cucumber, yogurt-based drinks like lassi, and nimbu paani are excellent natural ways to stay cool and hydrated.

Outside the Home

Avoid going outside between 11am and 4pm whenever possible — these are peak heat hours across most of Pakistan from May through August. If you must go out, wear loose, light-colored cotton clothing. Synthetic fabrics trap heat and prevent sweat from evaporating.

Carry water with you. Never get into a parked car without checking the interior temperature first — cars can reach dangerous temperatures within minutes in direct sunlight. Never leave children, elderly people, or pets in a parked vehicle.

If you work outdoors, take shade breaks every 20 to 30 minutes. Drink small amounts of water frequently rather than large amounts all at once.

Warning Signs-Go to Hospital Immediately If You See These

Do not wait and see. In excessive heat, conditions can deteriorate from mild to life-threatening within an hour.

Go to an emergency room immediately if someone shows confusion or seems disoriented, stops sweating despite extreme heat, has a body temperature above 39°C, cannot stand or has fainted, is vomiting repeatedly and cannot keep water down, or has a rapid, weak pulse.

While waiting for medical help or transport, move the person to the coolest available space, remove extra clothing, and apply cold wet towels to the neck, armpits, and groin area. Do not give water to someone who is unconscious.

Final Thoughts

Excessive heat in Pakistan is no longer a seasonal inconvenience. It is a public health emergency that returns every year, kills quietly, and disproportionately harms the people who already have the fewest resources to protect themselves.

The good news is that most heat-related deaths are preventable. Awareness, preparation, and fast action make an enormous difference. Knowing the difference between heat exhaustion and heat stroke. Keeping ORS at home. Checking on an elderly neighbor during a heatwave alert. Reminding a child to drink water. These are small things that add up to saved lives.

Pakistan's summers are getting hotter. The only reasonable response is to get better at surviving them — and that starts with understanding exactly what we are up against.

Frequently Asked Questions

Is Excessive Heat Dangerous at Night Too?

Yes, and this is something most people do not realize. The body recovers from daytime heat during the night — but only if nighttime temperatures drop enough. During the 2024 Karachi heatwave, nighttime temperatures stayed above 32°C for several consecutive days. With no electricity for fans, people had no way to cool down overnight. This continuous heat exposure without any recovery period is what makes heatwaves so deadly.

How Is Excessive Heat Different From Normal Summer Heat?

Normal summer heat is uncomfortable but manageable for a healthy adult. Excessive heat — defined by health authorities as temperatures significantly above what is typical for a region, often combined with high humidity — overwhelms the body's ability to self-regulate. In Pakistan's context, temperatures above 42°C combined with humidity above 60% create heat index values that feel like 50°C or above. At that point, even short outdoor exposure becomes dangerous.

Can Excessive Heat Affect Mental Health?

Yes. This connection is often overlooked. Heatwaves are consistently linked to increased irritability, anxiety, disrupted sleep, and worsening depression. People with existing mental health conditions are at higher risk. Some psychiatric medications also reduce the body's ability to tolerate heat, creating a double vulnerability.

What Should Children Drink During a Heatwave?

Water is the best option. Avoid cold, sugary sodas — they provide temporary relief but contribute to dehydration. Coconut water, diluted fruit juices, and lightly salted lemonade (nimbu paani with a small pinch of salt) are good options for children. If a child is vomiting or has diarrhea in the heat, ORS is essential and should be started immediately.