The Heat Already Knows: Summer Is the Season That Tells the Truth

There is a particular quality to Mediterranean light in late June — the way it arrives not as illumination but as weight, pressing down on the limestone until the whole city holds warmth like a fired kiln long after the sun has gone. I have been in Valletta long enough now to know this light intimately. And I have been in enough other places to know that the body, unlike the stones, was never designed to simply absorb it.

France is counting its dead. Around a thousand additional deaths attributed to the current heat wave, a number that arrives not as abstraction but as a particular kind of grief — people who woke up on ordinary mornings and were undone by the temperature. The record-breaking heat across Europe this summer is the kind of story that gets filed under climate and policy and atmospheric science, but it belongs here too, in the body, which has limits that no amount of wellness optimism overrides.

What strikes me about heat illness is how consistently it hides in plain sight. The mechanism is almost elegant in its cruelty: your body begins suppressing thirst precisely when it most needs you to drink. This is true for healthy adults under sufficient heat load. It becomes more acute for anyone on medications that interfere with thermoregulation — and GLP-1 drugs, which have become as common in certain circles as multivitamins, do exactly this. They blunt thirst response. They slow gastric emptying, which also affects how the body processes fluids. In serious heat, that combination matters.

But I don't want to write about medication. I want to write about something simpler, which is that most of us are chronically, quietly under-hydrated on ordinary days, and heat turns that quiet deficit into something urgent. The research on hydration and cardiovascular load is consistent: the heart works harder in dehydrated states, blood thickens slightly, blood pressure fluctuates. Watermelon — which I have been eating with salt and mint since Singapore taught me that combination — is about ninety-two percent water, with meaningful amounts of lycopene and citrulline, both of which show real promise in cardiovascular research. It is not a cure for anything. It is simply food that the body recognises as useful, especially when the air outside feels like the inside of an oven.

There is also this: the body's relationship to heat is not purely physical. Europe's thousand extra deaths are older people, mostly, living alone, in apartments without air conditioning, in the kind of social isolation that health systems are only beginning to measure properly. Loneliness is a heat risk factor. It is also, quietly, a health risk factor in every season.

Drink more water than you think you need tomorrow — not sports drinks, not coffee, not the glass of rosé that feels like hydration in this light. Water, cold, with something in it if that helps. Start before you're thirsty. The body, like most things worth attending to, responds best to being anticipated rather than rescued.