Lots of people struggle to get enough sleep — and the responsibility for fixing the problem tends to fall on the individual. Experts offer advice like reducing screen time, exercising more, or just going to bed earlier in the evening.
But many restless nights can’t be solved with blackout curtains, ear plugs, or other typical suggestions. On average, Black adults in the U.S. get poorer sleep than white adults — often for reasons outside of their control. A growing number of experts argue that in order to address such racial disparities, health professionals need to start discussing sleep within the complex tapestry of a person’s life and surroundings.
“A large proportion of the disparities in sleep are really due to social and environmental factors” such as noise pollution, said Mercedes Carnethon, vice chair of preventive medicine at Northwestern University’s Feinberg School of Medicine and an expert on racial disparities in cardiovascular disease.
The implications of these sleep disparities are far-reaching. The medical world has known for decades that habitually poor sleep increases the risk for heart disease. If more people regularly got the recommended seven to nine hours of restful sleep, experts assert, the incidence of heart disease — the most frequent cause of death in the U.S. — could fall substantially. Earlier this year, the American Heart Association went so far as to add getting a good night’s sleep to its central recommendations for improving cardiovascular health.
Consistently better sleep for all, in turn, could help narrow the existing racial, ethnic, and socioeconomic disparities in cardiometabolic diseases, according to Lauren Hale, a professor of preventive medicine and expert on sleep behavior at Stony Brook Medicine. About 229 of every 100,000 Black Americans died from heart disease in 2020, compared to 170 deaths per 100,000 white Americans. Some researchers have estimated that at least half of the racial disparities in cardiometabolic disease risk can be traced back to differences in the sleep patterns of Black and white Americans.
“Sleep hygiene recommendations do not address underlying, structural causes of disparities,” Hale said. “The real challenge is translating the science of what we know about sleep and its disparities into scalable, sustainable interventions.”
Sleep is notoriously challenging to study, especially as it happens under messy, real-world circumstances, outside of the controlled research laboratory.
For starters, “sleep is so multi-dimensional,” said Kristen Knutson, an associate professor of sleep medicine and epidemiology at Northwestern’s Feinberg School of Medicine. From a health perspective, what matters is not just how long a person sleeps but also factors like the quality of their sleep and when they sleep. About one-third of adults in the U.S. report regularly getting fewer than seven hours of sleep per night, according to the Centers for Disease Control and Prevention. And that likely misses a substantial proportion of people who wake up throughout the night, even if they’re not aware of it.
Despite the prevalence of common sleep challenges, “the field of sleep medicine has really focused on clinical sleep disorders” such as obstructive sleep apnea and insomnia, said Natasha Williams, an associate professor of population health who focuses on behavioral sleep medicine at New York University’s Grossman School of Medicine.
These medical conditions can be more clearly measured, diagnosed, and treated than everyday sleep issues. To be sure, there are also vast racial and socioeconomic disparities in the rates these serious conditions are diagnosed and treated. But this all-encompassing focus often overlooks the millions of people — a disproportionate number of whom are Black — who don’t have a diagnosable sleep disorder but whose chronic lack of restful sleep is putting them at higher risk for cardiometabolic disease and death.
“The fundamental cause of sleep inequities is structural racism.”
Dayna Johnson, assistant professor of epidemiology at Emory
Another substantial challenge is disentangling sleep from all of the other factors — such as diet, exercise, or weight — that can contribute to cardiovascular disease. “A lot of adverse health behaviors are common bedfellows,” Carnethon said. For example, experiencing poor sleep makes it less likely a person will exercise or eat healthfully, she said. And lack of healthful eating or exercising can then lead back to poorer sleep, further propelling the harmful cycle.
These feedback loops can further hasten cardiometabolic deterioration. For example, chronic poor sleep increases the odds of developing conditions including obesity, hypertension, and diabetes, all of which are more prevalent in Black populations. Each of those conditions then further increase the chances someone will have poorer sleep; someone with diabetes, for example, might get up more often in the night because high blood sugar can make people need to urinate more frequently. The cycle can exacerbate their existing conditions and put them at risk for new ones.
Regardless of the contributing factors to poor sleep, from lifestyle to comorbidities, “the fundamental cause of sleep inequities is structural racism,” said Dayna Johnson, an assistant professor of epidemiology who studies the origins of sleep health disparities and their impact on cardiovascular disease at Emory University’s Rollins School of Public Health.
Racism undercuts the opportunity for restorative sleep and cardiovascular health in numerous, insidious ways.
For one, researchers have long known that chronic stress diminishes sleep quality. “Some proportion of [sleep] disparities are most certainly intertwined with psychological distress due to socioeconomic factors, interpersonal stress, racism, and discrimination,” Carnethon said.
Hale agreed, noting that, “In order for one to sleep well, one needs to feel safe — and not have a heightened sense of alertness that, unfortunately, many members of our society carry with them every day. … That heightened vigilance, that fear of discrimination or maltreatment or distrust of your neighbors, is part of the reason why we believe we see racial and ethnic disparities in sleep.”
In general, people with higher socioeconomic status tend to get better sleep. But that restful benefit of rising fortunes does not track equally across all races. Studies have shown that highly educated, high-income Black Americans still sleep more poorly than their white peers, taking longer to fall asleep and spending more time lying awake in bed. In fact, researchers have found that disparities in sleep are actually more vast between Black and white professionals as opposed to between Black and white blue-collar workers. One explanation for this pattern, according to some researchers, is that Black people at higher socioeconomic levels may find themselves more frequently in the minority at work or in their neighborhoods, increasing their daily experiences of racism and discrimination.
“In order for one to sleep well, one needs to feel safe.”
Lauren Hale, professor of preventive medicine at Stony Brook Medicine
Historic patterns of housing discrimination, which have created generations of wealth and environmental inequities, also impact sleep disparities. Redlining policies, which until the late 1960s legally prevented Black Americans from buying homes in certain areas, created neighborhoods with much poorer conditions for sleep, including higher levels of noise, light, poverty, and air pollution.
Decades of fallout from these racist policies have meant that scientifically validated sleep hygiene recommendations, such as a quiet, dark, cool sleep environment, are often out of reach for those already most at risk for cardiovascular disease and death.
For example, a person living in a low-income urban area without access to air conditioning might face multiple barriers to quality sleep. Opening windows could invite in excessive noise, light, and air pollution, while keeping windows closed could create a stifling environment. “As temperature goes up, sleep quality goes down,” Carnethon said. And as climate change makes nights even warmer, people living in city neighborhoods lacking green spaces — who are already disproportionately at risk for cardiovascular disease — face even more sleepless nights ahead. “The environment and climate equity also play a role in sleep disparities,” Carnethon said.
Those with lower household incomes, who, due to long-standing and structural social inequities, are more likely to be Black, are also more likely to face financial, food, and housing stressors, further pushing off restful sleep. And they are more likely to work multiple jobs, often involving shift work, which makes it harder to keep a regular sleep schedule. People living with more family members or in higher-density apartment buildings may also have less control over noise levels when they’re trying to rest.
This summer, in a Journal of Clinical Sleep Medicine paper, Johnson and two colleagues coined a new term for these pockets of sleep deprivation: sleep deserts. Like food deserts, these are geographical areas where quality sleep is more difficult to obtain, by no fault of the individuals living there.
Johnson and others are hoping to spread the message that sleep poverty, like economic poverty, “is not just individual behavior,” she said. “We have to consider the context in which people live.”
And ameliorating these deeply rooted forces behind health poverty is going to require substantial, structural shifts.
In the absence of rapid reprieve from the insomnious impacts of structural racism, experts in the field of sleep and cardiovascular health suggest additional approaches that might help begin to reduce disparities in the meantime.
It will be essential, for example, to ensure that recommendations for individuals are effective and practical for those they are trying to reach, Knutson said. “It’s not as simple as saying, ‘Hey, go out and sleep more, exercise better, eat better,’” Knutson said. “There are only 24 hours a day, and there are a lot of competing priorities for individuals. Getting a paycheck, paying the bills, and taking care of your kids — those are going to take priority. Not everyone has the luxury and privilege of having sufficient time for sleep.”
The multidimensional nature of sleep, although tricky to study, also “gives us more opportunity to think of a way to improve sleep that isn’t just about quantity,” Knutson said. “Can we make it more regular or better quality? Thinking about all the dimensions of sleep health, which one can we act upon to improve that will be beneficial for their cardiovascular health?”
“It’s not as simple as saying, ‘Hey, go out and sleep more, exercise better, eat better.’ There are only 24 hours a day.”
Kristen Knutson, associate professor of sleep medicine and epidemiology at Northwestern
Knutson acknowledged that many people might realistically only have time for five or six hours of sleep. If that’s the case, she suggested emphasizing sleep regularity, that is, ensuring that sleep happens at the same time each day. Hale added that this approach is especially important for people who work outside of standard business hours: “Even if you must work shift work, work it in a way that you are not changing your shifts every single night,” if possible.
Knutson would also like to see more research focused on finding “inexpensive, attainable ways to improve sleep … that people will use and will work.” She said, for example, that although ear plugs sound like a reasonable solution for mitigating excess noise, many people don’t feel safe wearing them while sleeping for fear they might not hear an intruder. As an alternative, she suggested dulling external sounds with white noise, which can come from a low-cost machine or free phone app and can be more finely controlled and feel less obstructive.
Improving sleep with an aim of reducing cardiovascular disease disparities will also require larger improvements at home and in the community. “In order for us to truly be effective in eliminating sleep inequities, we have to think about the broader context in which [people] live,” Johnson said. As one illustration, she is involved with a program that helps people check and improve their home’s insulation and ventilation, which can support sleep as well as reduce money spent on heating and cooling.
Educating more physicians of color and more physicians generally around sleep could have an outsized positive impact in communities with higher risk for heart disease, Johnson added. In a brief primary care visit, doctors often focus on immediately measurable, treatable clinical conditions, such as weight, high blood pressure, or diabetes, rather than sleep — even though sleep patterns often underlie the risks for these conditions, multiple experts told STAT.
What will really move the needle on sleep equity for the long run, however, are changes to larger policies, experts said. “That is what determines the neighborhood structure, including the amount of money that’s allocated toward public health,” Johnson said. Things like more robust rules around levels of air and noise pollution could help create healthier sleep environments, especially for communities already at highest risk for heart disease — but only if they are routinely and equitably enforced, Johnson noted.
Hale and her colleagues found that general “investment in communities is associated with improvements in sleep health” — even when those investments seemed to have nothing to do with sleep itself. For example, in a 2021 Sleep paper, they described how, over a three-year period, individuals in a predominantly Black and low-income Pittsburgh neighborhood who lived close to new community assets — such as a new grocery store, park, or community center — showed improved sleep compared to those who lived farther away from these investments.
“The idea is, if you improve environments and communities, there will be a wide range of benefits for its residents,” Hale said.
Another, seemingly unrelated policy has many sleep experts cautiously hopeful about the future.
School districts around the country have been pushing back daily start times. Whether a high school student starts school at 7:30 a.m. or 8:30 a.m. might seem of little consequence for their risk for cardiovascular disease several decades later. But racial disparities in sleep begin before adulthood, and the risks for developing heart disease are cumulative across people’s lifetimes. “To the extent that cardiovascular health starts younger, we should be addressing these disparities in sleep as soon as possible,” said Hale. Research also shows later start times improve young people’s overall health and learning, which could potentially contribute to shrinking socioeconomic disparities later.
“The challenge of all health education is getting people not only to listen, but to really internalize and hear what’s being said, and then to change their behaviors,” Hale said. But in many cases involving health disparities, “when you have a structural condition that changes, then [behavior] change will follow” — a rising tide to lift all ships.
Other nationwide policies could help further reduce disparities in sleep and heart health. Johnson pointed to the positive health implications of passing a national livable minimum wage: If individuals could sustain their households on a single, daytime job, they could have more time — and less chronic stress — for sleep.
“These policies at a federal level are what are really going to help make a large impact on sleep and equity,” Johnson said.
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