88 Time August 17/August 24, 2020
For as long as seemay Chou Can remember,
she has gone to bed at midnight and woken around
4:30 a.m. Chou long assumed that meant she was a
bad sleeper. Not that she felt bad. In fact, sleeping
just four hours a night left her feeling full of energy
and with free time to get more done at her job lead-
ing a research lab that studies bacteria. “It feels really
good for me to sleep four hours,” she says. “When I’m
in that rhythm, that’s when I feel my best.”
Still, in an effort to match the slumber sched-
ules of the rest of the world, she would sometimes
drug herself—with melatonin, alcohol or marijuana
edibles—into getting more sleep. It backfired. “If I
sleep seven or eight hours, I feel way worse,” she says.
“Hung over, almost.”
Although the federal government recommends
that Americans sleep seven or more hours per night for
optimal health and functioning, new research is chal-
lenging the assumption that sleep is a one-size-fits-all
phenomenon. Scientists have found that our internal
body clocks vary so greatly that they could form the
next frontiers of personalized medicine. By listening
more closely to the ticking of our internal clocks, re-
searchers expect to uncover novel ways to help every-
body get more out of their sleeping and waking lives.Human sleep is largely a mystery. We know it’s im-
portant; getting too little is linked to heightened risk
for metabolic disorders, Type 2 diabetes, psychiatric
disorders, autoimmune disease, neuro degeneration
and many types of cancer. “It’s probably true that
bad sleep leads to increased risks of virtually every
disorder,” says Dr. Louis Ptacek, a neurology pro-
fessor at the University of California, San Francisco
(UCSF). But details about what’s actually going on
during shut-eye are sparse. “We know almost noth-
ing about sleep and how it’s regulated,” says Ptacek.
Some people are morning larks, rising early,
and others are night owls, who like staying up late.
Those patterns are regulated by the body’s circadian
rhythm, a 24-hour internal clock. People can manip-
ulate their circadian rhythm through all kinds of ex-
ternal factors, like setting an alarm clock or expos-
ing themselves to light. But the ideal sleep duration
has long been thought to be universal. “There are
many people who think everyone needs eight to eight
and a half hours of sleep per night and there will be
health consequences if they don’t get it,” says Pta-
cek. “But that’s as crazy as saying everybody has to
be 5 ft. 10 in. tall. It’s just not true.”
Ptacek and his wife Ying-Hui Fu, also a professorof neurology at UCSF, are pioneers in the relatively
new field of sleep genetics. About a decade ago, Fu
discovered the first human gene linked to natural
short sleep; people who had a rare genetic mutation
seemed to get the same benefits from six hours of
sleep a night as those without the mutation got from
eight hours. In 2019, Fu and Ptacek discovered two
more genes connected to natural short sleep, and
they’ll soon submit a paper describing a fourth, pro-
viding even more evidence that functioning well on
less sleep is a genetic trait.
The researchers are now collecting data on short
sleepers in order to figure out just how rare these mu-
tations are. “If we can get a better understanding of
why their sleep is more efficient, we can then come
back and help everybody sleep more efficiently,” Fu
says. Among the participants is Chou, who also hap-
pens to work at UCSF. One day at a faculty meeting,
she and Ptacek chatted about his work. She imme-
diately recognized herself when he described short
sleepers. “I had never heard of this. But once I started
reading about it, it was sort of an epiphany.”
Chou doesn’t know yet if she has the identified ge-
netic variants. But after the researchers interviewed
her about her family’s sleeping patterns, she realized
her mom is also a short sleeper. “I have memories of
when I was younger, and my dad being frustrated
with her for staying up really late, but she always
seemed fine,” she says. The researchers took blood
samples from both women.
Doctors once dismissed short sleepers like Chou
as depressed or suffering from insomnia. Yet short
sleepers may actually have an edge over everyone
else. Research is still early, but Fu has found that
besides being more efficient at sleep, they tend to
be more energetic and optimistic and have a higher
tolerance for pain than people who need to spend
more time in bed. They also tend to live longer. Chou
says the first three hold true for her; by nature, she
is sunny and positive, and though she often finds
bruises on her body, she usually doesn’t remember
getting them. “I find it annoying how much people
complain about little physical pains,” she says.
So far, these are just intriguing observations. But
by studying genetic short sleepers, Fu and Ptacek be-
lieve they’ll eventually learn lessons for the rest of us.
“As we identify more and more genes and we think
about the pathways in which they function, at some
point, a picture is going to emerge, and we will begin
to have an understanding of how sleep is regulated
in greater detail,” Ptacek says. This, they hope, will
lead to targeted treatments, like pills or vitamins, to
improve sleep efficiency in everyone.
Researchers are also looking beyond sleep to other
circadian bodily processes that might benefit from
a personalized or targeted approach. While a mas-
ter clock in the brain acts like a conductor, setting
time for the whole body, the rest of the body is likeThe next frontier of
personalized medicine:
your inner clock
WE USED
TO THINK
EVERYONE
NEEDED EIGHT
HOURS OF
SLEEP. NOT SO,
ACCORDING TO
NEW SCIENCE
By Mandy
Oaklander
Sleep