But Do We Use Only 10% of Our Hearts? A Look at 7 Other Medical Myths

Alok Jha in the Guardian:

The seven myths, published today in the British Medical Journal, were based on ideas and conversations the authors had heard endorsed on several occasions - and which many physicians thought were true.

"Whenever we talk about this work, doctors at first express disbelief that these things are not true. But after we carefully lay out medical evidence, they are very willing to accept that these beliefs are actually false," said Vreeman.

Everyone must drink at least eight glasses of water a day

This advice is thought to have originated in 1945 from the Nutrition Council in the US, which suggested people needed to consume 2.5 litres of water a day. But Vreeman said the water contained in food, particularly fruit and vegetables, as well as in milk, juice, coffee and soft drinks, also counts towards the total.

We only use 10% of our brains

"The myth arose as early as 1907, propagated by multiple sources advocating the power of self-improvement and tapping into each person's unrealised latent abilities," say Vreeman and Carroll. "The many functions of the brain are highly localised, with different tasks allocated to different anatomical regions. Detailed probing of the brain has failed to identify the 'non-functioning' 90%."