Illustration: LEAL
Why is 30C more of a scorcher in April than in August?

Why is 30C more of a scorcher in April than in August?

The dangers of surprise out-of-season heatwaves

Yolanda Veiga

Friday, 28 April 2023, 18:43


We are nearing the end of April, yet in many places in Spain it feels like summer.

“This week we will have temperatures between six and ten degrees higher than the norm for this time of year. The temperatures reached would usually be for the second half of June,” confirmed Rubén del Campo, spokesman for the Spanish meteorological agency (Aemet) earlier this week.

And he warned that, as the week comes to a close, it would get worse. Yes, worse, because this heat has come at the wrong time of year, no matter how many say that they love it, it is unhealthy for us.

It’s no good for the environment either: “The risk of fire and drought increases as there is more evaporation,” warned the weather agency.

“These heatwaves are more dangerous in April than in July because it means a sudden shift from the winter to summer wardrobe. When the transition is so fast, the body does not have time to adapt well, not even just a bit. In August, even when it reaches 30+ degrees, we have had time to adapt little by little, but that’s not the case now. Going from cool to hot so suddenly has consequences for the body and can be serious,” warned Lorenzo Armenteros del Olmo, spokesperson for the Spanish society of general and family doctors (SEMG).

Despite this general rise in temperatures, the heatwave will be more noticeable in certain areas.

“This week temperatures are expected to exceed 38 degrees in some parts of the south,” according to Rubén del Campo, who pointed out that the average temperature in Spain for April is 11.9 degrees.

This week will see much higher readings. “Our bodies can deal well with temperatures up to 25 degrees, but every degree above that affects us a lot. And that’s not factoring in humidity. When the heat is dry, the body adapts better, since sweating eliminates that hot feeling but, when it’s sticky, our systems don’t function so well,” warned the SEMG specialist.

In fact, just as the wind increases that feeling of cold in winter, so too can humidity multiply that suffocating feeling when it is very hot. And it is not just a feeling, it can be quantified: 34 degrees in a location with a relative humidity of 70% will seem like 47 degrees, and as much as 54 when reaching 36 degrees, according to Aemet’s graphs.

What are the most serious consequences of this excessive heat, especially when out of season? Two: on the one hand, heat stroke; on the other, heat stress. “When we are exposed to very high temperatures for a long time, we can suffer heat stroke, which can be quite dramatic because it results in cold sweats, dizziness, fainting... It is easy to diagnose,” Armenteros said.

But this is not quite the case with heat stress.

“When high temperatures are maintained for days, the heat affects the body in stages, especially hitting vulnerable people such as the elderly, children... Water and salts are lost and not replaced; the elderly stop feeling thirsty; both the elderly and children experience difficulty in regulating their body temperature, and that can lead to acute metabolic decompensation.

“The kidneys start to fail because they are unable to get rid of the toxic substances that they should expel and so these toxins accumulate, sometimes causing arrhythmia [irregular heartbeat],” said the specialist.

“Heat stress causes a gradual deterioration” but, as it manifests itself “in such an underhanded way”, the doctors themselves find it troubling to diagnose.

“During last year’s heatwaves we attended to lots of elderly patients who were clearly unwell. They were suffering from dizziness, nausea, cramps... but there was nothing organically wrong with them to justify all those symptoms. It was simply heat stress,” Armenteros del Olmo said.


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