Heatwave Across Europe | What Happens To Your Body Under Extreme Heat?

As your internal temperature climbs, you can go from dehydration to muscle cramps, confusion, and even a coma.

World Environment Day: Heatwaves are spreading across the world. Here's what your body faces in the extreme heat.

(Image: Aroop Mishra/Quint FIT)

(This story was republished from FIT's archives in the context of the heatwave sweeping across Europe.)

The India Meteorological Department (IMD) predicted severe heatwaves across India, adding that April 2022 will be one of the hottest months in recorded history.

March 2022 was the hottest it has been in over 122 years.

From Maharashtra to Odisha, from Gujarat to Delhi, several places are set to record temperatures above 40 degrees celsius.

With heatwaves spreading their fingers across the world, we've already discussed the environmental impact of heatwaves.

And the human cost.

But what exactly happens to your body as the temperature gets hotter? What are the physiological and biological effects you have to endure as the heat goes from a warm 30 degree Celsius to the horrific 45-50 degree heat we face in peak summers every year?

And with temperatures already touching 45 C in April 2022, this is more important than ever.

What Happens To Your Body As The Temperature Rises?

Heatwaves are scorching their way across India right now.

Humans are endotherms - which is just a fancy way of saying we're warm-blooded animals.

This means our internal temperatures stay stable despite external temperature changes. So if it's hot outside, our body tries to get cooler, and if it's cold outside our body tries to get warmer.

For context, our internal temperatures are maintained around 36.8 degrees Celsius, give or take 0.5 degrees.

When the outside temperature falls, your body generates heat to compensate for the difference. When the outside temperature is higher than your body's internal temperature, your body releases the heat by sweating. Which is why you sweat in the heat, and don't sweat in the cold.

But while humans are remarkably capable of survival, you can't fight biology and nature.

As the temperature rises or falls beyond a certain point, your body's ability to compensate reduces. So from 0 degrees Celsius to 50 degrees Celsius, what happens to your body?

At 0 degrees your body is cold. It has to compensate for the 36-degree difference in external temperature and your core body heat. This is hard, so you wear layers, sweaters, blankets and gloves to stay warm. Or get close to someone you love for body warmth.

At these temperatures, being out in the cold without any clothes on can lead to many things that sound cool but really aren't - like hypothermia, windburn, frostbite, and if you suffer from breathing or heart problems, you could suffer some serious consequences.

As the temperature rises, your body has to generate less heat. At 7 degrees celsius, the weather is cold but still tolerable. As it rises to 12-15 and even 20 degrees, it stays quite comfortable, and you may start taking those layers off.

Now the most pleasant outside temperatures lie in the 15-22 temperature range, with no major problems for most people. Your body compensates for this external temperature difference by warming itself up from the inside.

But our temperatures right now are more in the range of 40-45 C.

What Happens To Your Body Under Intense Heat: A Step-by-step Guide

With temperatures touching 45 °C in April 2022, what will the summers bring?

• If your body's internal temperature falls by two degrees below 37, you'll experience hypothermia. Now when it starts RISING, you start experiencing something called HYPERthermia.

• At 38 degrees Celsius you start feeling very tired, and you start sweating profusely to cool yourself off.

• As your temperature climbs higher, your kidneys start to struggle to keep up with the excess sweating and dehydration. You're losing a LOT of fluids at this point. In the next few minutes you're likely to experience confusion and fatigue.

• Meanwhile. your muscles start to cramp because you've lost so much sodium and other electrolytes through the sweating....and drinking more water just makes this worse, because you're diluting your body's sodium reserves even further.

• What you need is an electrolyte drink, but you can't get one because you don't know this.

As your cramps get worse, soon you'll be in pain so intense you can barely stop screaming, let alone walk.

• As you approach 39 C, your heart has trouble pumping blood. Your body is trying to release the heat in any way it can, which makes your blood vessels dilate fully to let the heat dissipate. But this lowers your blood pressure because the blood has more space to move through.

• At the same time, the LOSS of fluids, means the heart has less volume of blood to pump, which is around the time you start feeling faint or when you lose consciousness. Now you're lying passed out in the heat, and your internal temperature is slowly getting hotter.

At 40 degrees Celsius body temperature, is when you start to die. Your organs slowly start to fail. You can suffer heatstroke and die from this in under 30 minutes if you don't receive immediate cooling and hydration.

• At 41 degrees Celsius you could suffer a stroke, heart failure, multiple organ failure and just drop dead where you stand...and that's...usually...a bad thing.

• Imagine an egg in a microwave. That's what happens to the human body at this point. The heat starts to denature the protein in your body, and in short....you get cooked alive.

• Recovering from this point is very difficult. And I'm not the one saying it. That's from Dr. Sumit Ray, who has worked as a critical care specialist for over 25 years.

What Can You Do To Cope With The Heat?

Stay hydrated with electrolyte drinks.

We can only cope with so much heat. Make sure you stay hydrated, cool, and comfortable in the heat.

Drink plenty of electrolyte-rich drinks - nimbu paani, oral rehydration solution, coconut water, buttermilk, and avoid prolonged direct exposure to the sun.

If you're middle-class like me, you can afford this at least sometimes.

But what happens to the lakhs of people who can't afford to do that? What happens to the poor family of four who can barely afford a home and three-square meals, let alone cold drinks, fans and air conditioning.

Well until we stop climate change or find a solution to this crisis, whether on an environmental or governmental scale...they'll unfortunately, depressingly, just have to get cooked alive.

Which is the grimmest reality of this heatwave.