554 29 OCTOBER 2021 • VOL 374 ISSUE 6567 science.org SCIENCE
cine researcher at New York University’s
(NYU’s) Langone Health. “We can’t do
without it.” Besides leading to drowsiness
and impaired cognition, lack of sleep also
takes a toll on the body.
As early as the 1980s, studies linked
sleep apnea and shift work with hyper-
tension and coronary heart disease. When
we sleep, our blood pressure goes down,
Johnson explains. “We give our blood
vessels a break, essentially,” she says. But
if sleep is interrupted or shortened, the
body maintains a higher blood pressure
at night—what physicians call nocturnal
hypertension—which raises the risk of
heart disease and stroke. Many stud-
ies have shown Black shift workers have
higher chances of developing hypertension,
compared with white shift workers.
Recent studies have firmed up the link
between poor sleep and cardiovascular
disease in people of color. A 2017 pa-
per published in the Proceedings of the
National Academy of Sciences showed that
among 426 people in three U.S. cities, Black
people had a 12.5% higher cardiometabolic
risk—the chances of having a cardio-
vascular event, such as a heart attack or
stroke, or developing diabetes—than white
people. They also slept 40 fewer minutes
per night than white people and spent
10% less time asleep while in bed, a mea-
sure of sleep efficiency. The researchers
estimated that together, those factors ac-
counted for more than half of the racial
difference in cardiometabolic risk.
Poor sleep may also contribute to worse
outcomes in Black people with heart prob-
lems, a 2018 study found. Black patients
who slept fewer than 7 hours at night in the
month after a heart attack or episode of un-
stable angina were at greater risk of another
event—or dying—compared with Black peo-
ple who slept more. Reduced sleep did not
have the same detrimental effect for white
people with a similar cardiac health history.
The health impacts aren’t limited to
cardiovascular disease. When we don’t
sleep enough or our sleep-wake cycle is dis-
rupted, hormone imbalances prompt hun-
ger, which can cause overeating and could
contribute to obesity, Johnson says. Re-
searchers have also found that disturbed
and insufficient sleep causes alterationsin glucose metabolism that can contribute
to insulin resistance, a precursor to type
2 diabetes. Obesity and diabetes already
disproportionally affect people of color,
and researchers suspect sleep disturbances
could be making those conditions worse.
Sleep apnea could be having dire health
consequences among Hispanic and Black
people, says physician-scientist Alberto
Ramos at the University of Miami. Large
epidemiological studies have suggested
apnea and related breathing problems are
twice as likely in Hispanic people com-
pared with white people—and often go un-
diagnosed. In an observational study with
14,440 Hispanic people, Ramos and col-leagues found less than 1% of those with
apnea had a proper diagnosis.
Poor sleep and sleep apnea have been
linked to neurodegenerative diseases—
especially Alzheimer’s disease—in the gen-
eral population, Ramos notes. And, he adds,
“We know that Hispanics have a two to four
times higher risk for dementia.” Sleep apnea
is one possible contributor to elevated de-
mentia rates and cardiovascular disease—
racism and neighborhood noise and air
pollution are others—that Jean-Louis and
Ramos plan to investigate in the varied Black
and Hispanic communities in Miami. At the
recent event at Trinity Baptist Church, Jean-
Louis recruited 10 new participants.AFTER JEAN-LOUIS MOVED from San Diego to
New York City in 2000 to work at the State
University of New York Downstate Medical
Center in the heart of Brooklyn, he started
to look for ways to engage with the many
communities of color near his lab. But he
learned the hard way that being Black him-
self did not mean automatic rapport. When
Jean-Louis, a native of Haiti, showed up at
a neighborhood barbershop with a clip-
board and started to ask people about their
sleep habits, they didn’t take him seriously.
He soon learned to first build trust with
the barbershop owners, who would then
convince their clients to open up.
Once they did, Jean-Louis found many
misconceptions. For instance, he learned
many people in these communities do not
think of sleep apnea as a problem. “In their
minds snoring is a good thing—it means
you’re in deep sleep,” he says. But in fact,
snoring is a sign that you’re not breathing
well during slumber.
Later, when he moved to NYU, he sought
other trusted intermediaries. He and
Seixas teamed up to recruit volunteers,
nominated by their own communities,
to be “certified sleep educators.” After an
8-week training program on sleep health
and counseling, the educators provided
tailored advice and emotional support to
people in their community, and convinced
many to get screened and treated for sleep
apnea. During the pandemic, the educators
helped convey accurate scientific informa-
tion about COVID-19—an unintended ben-
efit that demonstrates how trusted they’ve
become, Jean-Louis says. “It was a great
surprise,” he says. “They were wonderful.”
Such educators can deliver tailored and
culturally relevant information. “A lot of
the guidelines and solutions do not take
into account the lived experience of mar-
ginalized communities,” Alcántara says.
The mostly white experts who recommend
a certain amount of sleep, Seixas says,
“blindly accept and assume that people GRAPHIC: V. ALTOUNIAN/SCIENCESPECIAL SECTION SLEEP2131 Brain
Poor sleep decreases
alertness, which can
contribute to accidents
at work and on the road.
Bad sleep also impairs
cognition and worsens
depression and anxiety
symptoms. Chronic
sleep problems may
predispose people to
dementia—particularly
Alzheimer’s disease.
2 Heart
People who don’t sleep enough
have a greater risk of developing
hypertension and are more likely
to have a heart attack or stroke.3 Pancreas
Sleeping less and at odd
hours disrupts the body’s
metabolism and increases
the chances of developing
obesity, insulin resistance,
and type 2 diabetes.Immune system
Sleep deprivation increases the odds of
catching the common cold and decreases
the efficacy of some vaccines.
Life span
People who routinely sleep less than 6 hours
each night are 12% more likely to die prematurely
than those who sleep 6 to 8 hours, according to
one large review study.
Impacts of poor sleep
Sleeping 6 hours or less per night has detrimental effects throughout the body.
Light and noise pollution, discrimination, stress, socioeconomic status,
and shift work are some of the factors that affect sleep in communities of color.