84 Time August 17/August 24, 2020
each of us carTs around a 3-lb. universe ThaT
orchestrates everything we do: directing our con-
scious actions of moving, thinking and sensing,
while also managing body functions we take for
granted, like breathing, keeping our hearts beating
and digesting our food. It makes sense that such a
bustling world of activity would need rest. Which
is what, for decades, doctors thought sleep was all
about. Slumber was when all the intricate connec-
tions and signals involved in the business of shut-
tling critical brain chemicals around went off duty,
taking time to recharge. We’re all familiar with this
restorative role of sleep for the brain— pulling an
all- nighter or staying awake during a red-eye flight
can not only change our mood, but also affect our
ability to think clearly until, at some point, it prac-
tically shuts down on its own. When we don’t get
enough sleep, we’re simply not ourselves.
Yet exactly what goes on in the sleeping brain has
been a biological black box. Do neurons stop func-
tioning altogether, putting up the cellular equivalent
of a do noT disTurb sign? And what if a sleeping
brain is not just taking some well-deserved time off
but also using the downtime to make sense of the
world, by storing away memories and captured emo-
tions? And how, precisely, is it doing that?
In the past five years, brain researchers have begun
to expose a hidden world of chemical reactions, fluids
flowing into and out of the brain, and the busy work
of neurons that reveal the sleeping brain is as indus-
trious as the waking one. Without good-quality sleep,
those critical activities don’t take place, and as a con-
sequence, we don’t just feel tired and cranky, but the
processes that lead to certain diseases may even get
seeded. One of the reasons we sleep, it now seems,
might be to keep a range of illnesses— including cogni-
tive diseases like Alzheimer’s and other dementias—
at bay. As Adam Spira, a professor in the department
of mental health at the Johns Hopkins Bloomberg
School of Public Health, puts it, “Sleep really should
not be seen as a luxury or waste of time. People joke
that they’ll sleep when they’re dead, but they might
end up dead sooner if they don’t sleep.”blame Polymath Benjamin Franklin, who averred,
“There will be sleeping enough in the grave”; ever
since, a culture of industry has rooted itself in the
human psyche— embedding the idea that activity, even
well into the night, is valued far more than daily rest.
In part that’s because while medical experts havelong recommended seven to eight hours of sleep
a night—including some time spent in deep, or
non-REM, sleep—exactly what our bodies are doing
during that time is less clear. Now, thanks to newer
technologies for measuring and tracking brain activ-
ity, scientists have defined the biological processes
that occur during good-quality sleep. That they seem
to be essential for lowering the risk of brain dis orders,
from the forgetfulness of senior moments to the more
serious memory loss and cognitive decline of demen-
tia and Alzheimer’s disease, may convince the Frank-
lins of the world that sleep is not for the lazy.
Experts in the field of Alzheimer’s are especially
excited, since there are currently no treatments for
the neurodegenerative disease, and sleep-based
strategies might open new ways to slow its progres-
sion in some and even prevent it in others.
“There has been a real renaissance in research
around the connection between sleep, sleep qual-
ity, sleep disturbance and dementia, especially Alz-
heimer’s dementia,” says Dr. Kristine Yaffe, profes-
sor of psychiatry, neurology and epidemiology at the
University of California, San Francisco. The National
Institutes of Health is currently funding at least half
a dozen new studies exploring how sleep may impact
dementia, and the Alzheimer’s Association created
a committee to promote more research in the area.
For decades, researchers thought sleep dis-What exactly is
your brain doing
while you sleep?
NEW
RESEARCH
ON ITS
PHYSIOLOGY
SHOWS WHY
WE NEED TO
TAKE SLUMBER
SERIOUSLY
By Alice Park
Sleep