Why extreme heat leaves you more exhausted than ever

Why extreme heat leaves you more exhausted than ever

Walking across the beach sand becomes a monumental effort. The fatigue is not just mental: your body feels heavy, drained, as if it had switched into hibernation mode. Those who suffer from it repeat the same pattern every summer, but they insist that this year the intensity is unusual.

The reason? Extreme heat triggers a series of physiological responses: blood vessels dilate, blood pressure tends to drop – those who already have high blood pressure notice a sudden dip that leaves them feeling wiped out – and metabolism slows down. The body prioritizes cooling itself and reduces muscle activity, a kind of "energy-saving mode" that is also seen in animals: stray cats lose weight and shed their fur uncontrollably.

The curious thing is that all this happens even though basic blood tests come back normal. One sufferer reports a blood pressure reading of 13/7, within the normal range, and yet the exhaustion is real. Plenty of people blame processed food, poor-quality water, or even aircraft contrails, although science points instead to the combined impact of humid heat and dehydration.

With the arrival of July and the heatwaves, the question is whether this widespread fatigue is a normal physiological phenomenon or a sign that something is changing in our exposure to extreme weather. For now, the only remedy everyone seems to agree on is one nobody can apply: not working and lounging in a pool.