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Is there a maximum amount of liquid a human can drink in a day? © Getty Images

Is there a maximum amount of liquid a human can drink in a day?

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Asked by: Robert Sedgwick, via Twitter

Your kidneys can remove 0.8 to 1 litres of water per hour, so theoretically you could drink 20 litres of water in a day. This assumes that you drink at an even pace, though.


There are cases of fatal water intoxication where the victim has drunk seven litres in three hours or less. This sudden influx of water increases the amount of water in the blood, which in turn reduces the concentration of minerals in the blood known as ‘electrolytes’ (these include sodium, potassium and magnesium).

The concentration of minerals becomes less than that inside the body’s cells, and so water moves into the cells by osmosis, to balance the concentration, and the cells swell. In the brain, this swelling is particularly dangerous because the brain is enclosed within the skull, and it cannot expand. So the increased pressure can result in brain damage and even death.

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Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


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