Most people require seven
to nine hours of sleep to have proper daytime
functioning, but some people can function
normally on less than six hours of sleep per
night owing to a gene mutation, says a study.
The genetic variant also appears to provide
greater resistance to the effects of sleep
deprivation, the researchers, who studied 100
twin pairs, noted.
People with p.Tyr362His – a variant of the
BHLHE41 gene – had an average nightly sleep
duration of only five hours, which was more
than one hour shorter than the non-carrier
twin, who slept for about six hours and five
minutes per night.
The twin with the gene mutation also had 40
percent fewer average lapses of performance
during 38 hours without sleep and required
less recovery sleep afterward – sleeping only
eight hours after the period of extended sleep
deprivation compared with his twin brother,
who slept for 9.5 hours.
“This work provides an important second gene
variant associated with sleep deprivation and
for the first time shows the role of BHLHE41
in resistance to sleep deprivation in humans,”
said Renata Pellegrino, senior research
associate at The Children’s Hospital of
Philadelphia in the US.
The study group comprised 100 twin pairs – 59
monozygotic pairs and 41 dizygotic pairs – who
were recruited at the University of
Pennsylvania.
Response to 38 hours of sleep deprivation and
length of recovery sleep were assessed in a
sleep lab. During sleep deprivation, cognitive
performance was measured every two hours
using the Psychomotor Vigilance Test.

RoyalRoy: More like my story.... lolllz.
4Hrs sleep in a day and am good to go.

Similar to mine as well.

Six hours does it for me, sometimes four