Scientists shed light on sleep through the ages
What starts with an “s” that seniors need more of than younger
adults, is great to get a bit of in the middle of the day and could
cause teens to turn to drugs if they don’t get enough of it?
The answer is sleep, according to several studies presented at the
annual meeting of the American Association for the Advancement of
A study conducted by researchers at the University of California San
Diego (UCSD) found that 68-year-old adults, on average, did better on a
simple memory test if they got more sleep.
In younger adults, aged 27 years on average, the quality of sleep
also affected how they performed on the same test.
“What mattered in the younger adults was sleep efficiency — that the
sleep was consolidated into one solid chunk,” said Sean Drummond, a
professor at UCSD’s department of psychiatry who led the study, adding
that sleeping soundly and uninterruptedly happens less and less
frequently with age.
“The most common change in sleep as we age is you wake up in the
middle of the night and you’re awake for some time, meaning you have
lower sleep efficiency,” Drummond said.
“In the older adults what we found is that waking up in the middle of
the night did not affect brain function or performance the next day but
if a young adult did that, it had significant detrimental effects on
brain function,” he said.
Another study looked at the possible benefits of napping.
“Our question first was could you get the same benefits from a short
daytime nap as a full night of sleep,” said Sara Mednick, also from
UCSD’s department of psychiatry.
“We started looking over a number of different tests beginning with a
visual learning test, which showed that if you had a 90 minute nap you
showed the same level of benefit as a full night of sleep,” Mednick
“There’s something very special about naps,” she said.
But not everyone has the luxury of being able to catch a few Zs in
the middle of the day, and as a substitute, many seek a caffeine boost.
But a double espresso works less well than a 20-minute nap, said
“On some tasks, such as those involving perceptual memory, caffeine
works as well as a nap,” said Mednick.
“But when the task involves the hippocampus, the area of the brain
devoted to explicit memories you can manipulate consciously, such as
learning a list of words or a phone number or name, with caffeine, your
memory for those kinds of tasks is decreased,” she said.
Meanwhile, another study found that “two significant clinical and
public health problems, sleep disorders and drug use in teens” are
Not only are teens who sleep less than seven hours a day more likely
to do drugs, but they are also likely to pass both their bad sleep and
drug-use behavior to friends and siblings.
“An adolescent who does not get enough sleep can influence a friend’s
sleep behavior, which increases the risk that the friend will use
drugs,” the study says.
Researchers at UCSD and Harvard University found that teens with a
friend who sleeps less than seven hours a night are 11 percent more
likely to sleep less than seven hours themselves and 19 percent more
likely to use marijuana than teens whose friends get a good night’s kip.
The US National Sleep Foundation recommends that teens get at least
8.5 hours of sleep and that adults, both younger and older, get at least
The study was the first to find that poor sleep habits and drug use
spread through teenagers’ social networks “like a contagion,” extending
to up to four degrees of separation — or to friends of friends of
friends of friends.