Writing on the hottest day of the year so far, sweat was never going to be very far from my mind. This is literally true: our brains are connected to every one of the innumerable sweat glands in our skins by neural pathways.
This regulation means that our evaporation cooling systems can respond to temperature changes very rapidly. No matter how hard we may try, we have no voluntary control over how much or when we sweat - these responses are controlled by the hypothalamus, clusters of nerve cells near the base of our brains.
These clusters of cells integrate information about the environment and the functioning of the body from all kinds of neural sensors and regulate our hormones as well as blood pressure, heart rate and sweating.
Given the vagaries of the English summer, writing about heat is always a risky idea. But in hotter periods the amount of salt in our sweat decreases (so we don’t lose too much) and this process of acclimatisation takes many days.
Even if the summer has become a washout by the time you read this, your sweat will remember the heat.
Dr Daniel Glaser is director of Science Gallery at King’s College London
