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Baseline temperature -

Human beings’ average temperature is around 8.6°F (37°C). Though it can range between 97°F (36.1°C) and 99°F (37.2°C).

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Fever -

Body temperature over 100.4°F (38°C) is considered a fever, which is a response from our immune system, usually to some form of infection or illness.

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So, what happens when it’s too hot? -

Our bodies have thermoregulation mechanisms, one of them being the process of sweating. But there are a few other ways our bodies try to keep us at a healthy temperature.

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Human thermoregulation -

The very first thing that happens when it’s too hot is your brain starts firing messages to your sweat glands to increase sweat production.

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Thermoregulation -

Then it’s all about pumping more blood to the skin, which is achieved by an increase in heart rate.

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Organs -

By pumping more blood to the skin, organs such as the kidney, liver, and intestines will have less blood supply.

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Impact on organs -

The impact of oxygen-rich blood being diverted away from vital organs to the skin may lead to organ failure as these become hypoxic (low levels of oxygen).

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Organ failure -

"When you have heatstroke, the body gets so hot it starts to denature proteins so [it] can't regulate your body temperature and therefore major organs can fail," said Mike Tipton, a professor from the University of Portsmouth.

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Risk of heart attack -

"You're more likely to have a heart attack as your cardiovascular system has to try harder to perfuse blood to your tissues than when it's cool," added Tipton.

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Why does the body try to get the skin warmer? -

It may sound counterproductive, but the body actually works to get the skin hotter than the outside temperature.

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Heat transfer -

The goal is to create a heat transfer phenomenon called convection, which will consequently help move the heat away from you. This, however, can put extra strain on a weak heart.

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Heat illness -

Excess heat can lead to different stages of heat illness, as follows (based on increasing severity): sunburn, fainting, exhaustion, and heatstroke.

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What happens when our thermoregulation system fails? -

This is when heatstroke occurs. When our body is unable to cool itself down, our internal temperature starts climbing up from our baseline to somewhere closer to 104°F (40°C) or 105°F (40.5°C).

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Heatstroke -

This rise of temperature then starts to affect the brain. This may feel like a dull headache at first, but things can get serious if brain tissue swells.

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Brain -

Dizziness, confusion, loss of consciousness, and even brain hemorrhage can occur as a result.

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Gut -

We have a barrier in our gut called the tight junction, which keeps bacteria from entering our bloodstream. When our body reaches such extreme temperatures, it stops doing its job.

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Gut -

This results in endotoxins being released into the bloodstream, which will likely trigger an inflammatory response from your immune system.

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Lack of research -

Because most research is conducted on people who actually died of heatstrokes, as well as animals in labs, there is still a lot we don’t know about it.

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High-risk groups -

While extreme heat can certainly kill anyone, it is believed that babies and those over 65 are at greater risk.

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Social background -

Those with lower incomes, who are more likely to live in apartments with no access to air conditioning, are also at greater risk.

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Electric fans -

Fans are used around the globe to keep people cool, but, according to a study, they are not suitable for all conditions.

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Electric fans -

The study did find that fans, when used in hot, humid conditions, were effective in cooling down body temperature and reducing cardiovascular strain.

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Electric fans -

However, fans didn’t seem to have the same effect in dry heat conditions, where they were shown to actually have the opposite effect, increasing body temperature.

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Dehydration -

Dehydration is also a fairly common cause of death when it comes to hyperthermia. We sweat more and blood thickens, increasing the risk of clotting.

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Dehydration -

Dehydration affects our cognitive abilities, which means that the brain will have problems sending the right signals to the body.

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How to stay safe -

There are a few steps you can take to stay cool during extreme heat and minimize the risks. These include staying indoors (or heading to somewhere cool with air con, such as a mall).

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How to stay safe -

Stay hydrated, minimize your exposure to sun rays, wear light, breathable clothing, avoid vigorous exercise, eat light foods, and have a tepid shower.

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How to stay safe -

And, of course, don’t forget to check on those who are at greater risk and keep informed about the weather forecast.

Sources: (Sky) (Canada's National Observer) (Annals of Internal Medicine)

See also: How to survive heat waves

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