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I am in an arid desert with a flask of caffeinated coffee. Should I drink it, or will its diuretic effects speed my demise?
Simon Maxwell
University of Edinburgh, UK
Drink the coffee. In a desert, dehydration is your biggest enemy, and any fluid intake is better than none. While caffeine is often labelled a diuretic, its effect is modest and works by blocking adenosine receptors, which indirectly increases urine production. However, in extreme heat and water scarcity, your body activates powerful water-conserving mechanisms – such as increased secretion of antidiuretic hormone – to retain fluid. These override the mild diuretic action of caffeine. In fact, research shows that for habitual coffee drinkers, the diuretic effect is negligible. The water in the coffee far outweighs any extra loss. So don’t worry: the coffee will help you survive, not hasten your demise.
Conrad Jones
Llansteffan, Carmarthenshire, UK
My advice would be to drink the coffee, then use the flask to collect whatever urine is produced, and reprocess it (drink it) later. That would delay your demise, certainly more than if you hadn’t drunk the coffee, and probably also more than if you had drunk it only once and watered the desert with your urine instead.
Robert Checchio
Dunnellen, New Jersey, US
I’m probably going to die eventually from dehydration, so I might as well drink the coffee while I’m able to enjoy it.
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