London - Those who claim, as Margaret Thatcher and Winston Churchill did, to need less than five hours’ sleep are met with disbelief by the rest of us.
But short-sleepers like the two former British prime ministers really do exist, and the evidence is they have a gene mutation.
While most of us need around eight hours’ sleep a night, feeling foggy and confused if we don’t get it, "natural short-sleepers" feel well rested after only four to six hours.
Researchers at University of California, San Francisco, found more than 50 families with members who require less than six and a half hours of sleep.
Taking one of these families, they isolated a mutation of the ADRB1 gene, which increased the activity of brain cells that promote wakefulness.
They found that those who needed little sleep shared the mutation, while their longer-sleeping relatives did not have it. And when scientists tweaked the same gene in mice, they slept for 55 minutes less than regular mice, according to the findings published in the journal Neuron.