The Inequality of Sleep

Racial inequality. Income inequality. There’s yet another contributor to inequality in the U.S. – and it’s closer to home than you think.

The most recent CDC data reveals that there is an inequality gap in our sleep. The long and short of it is this: wealthy white people enjoy better sleep than poorer people of other races.

The CDC’s survey of nearly 500,000 American adults revealed direct relationships between household income and sleep, as well as between race and sleep. Your race has a direct relationship with the length and quality of your sleep. Not only that, but further research suggests that sleep inequity starts from a young age.

Lack of sleep isn’t just about missing out on shuteye. Poor sleep contributes to a host of other issues, including decreased cognitive performance, impaired mental health, weight gain (and associated health conditions, like diabetes and cardiovascular disease), and up to a 30 percent greater risk of death.

All stemming from unequal sleep, these comorbid issues exacerbate larger systemic issues affecting ethnic and racial inequity. In this article, we review the latest research from the CDC and other institutions regarding sleep inequality, and the underlying factors that contribute to and worsen the sleep gap in America.

Keep reading to understand what explains this sleep inequality epidemic, and why it matters.

The Behavioral Risk Factor Surveillance System is a regular survey the CDC conducts to assess the health of our nation. They asked 444,306 adults in all 50 states and DC about their sleep patterns and found dramatic results.

Overall, more than one-third of adults regularly reported sleeping fewer than the recommended 7 hours minimum, leading the CDC to declare sleep deprivation a public health epidemic. Unfortunately, it also appears to be a socioeconomic epidemic.

The CDC also found an association between race and short sleep. One-third of white Americans report short sleep on a regular basis. That number seems alarmingly high, until you compare it with any other race — every single one of which reported short sleep to a larger extent than white Americans.

Black, multiracial, and Native Hawaiians and Pacific Islanders are the hardest hit by the sleep gap, with nearly half (44 to 46 percent) getting fewer than 7 hours of sleep every night.

The CDC data only looks at American adults. Unfortunately, other studies suggest this sleep gap starts much earlier — during childhood.

A 2017 meta-analysis reviewed the results of 23 studies, all observing the racial sleep disparities among American children between the ages of 6 and 19. Overall, their conclusions included the following:

• More than two-thirds of American teens sleep fewer than 8 hours on a regular basis. (While adults need 7 to 8 hours of sleep, adolescents actually need 9, which is why the researchers used 8 hours as their baseline for short sleep among teens.)
• White children were more likely to get sufficient sleep than other races, particularly black and Hispanic children.
• Black children were even more likely to get insufficient sleep than Hispanic children.
• These results held steady across age groups, whether the study looked primarily at school-age children (ages 6 to 13) or only teenagers (ages 14 to 19).

The negative impacts of the short sleep experienced by racial minority children showed up quickly. Those who had less sleep, and went to bed later (or woke up earlier), were more likely to be overweight five years later. On the other hand, those who experienced healthy sleep on a regular basis were more likely to demonstrate better academic performance and reasoning skills. The connection between sleep and academic performance is so strong that some studies have even concluded that better sleep on its own is a predictor of better grades.

Problematically, researchers have also observed that there isn’t a simple solution to the problem of sleep inequity among children. Some studies have tested implementing school-based interventions, such as a sleep education program administered to students in class or via text message.

While these programs have had some success, the success has been limited to white students — suggesting that there are major obstacles preventing minority children from getting adequate sleep beyond a lack of education about its importance. In other words, it’s not just about teaching children the importance of sleep; other systemic issues need to be addressed in order for them to implement those learnings effectively.

There are Racial Differences in Sleep Quality, Too

Study after study shows that minorities are more likely to get less sleep per night than white Americans. They’re also more likely to sleep too much. In the case of African Americans, they are 62 percent more likely to be long sleepers than white Americans.

We’ve talked a lot about short sleep, but long sleep can be equally damaging to quality of life, and physical and emotional wellbeing. Like short sleep, long sleep (defined as more than 9 hours per night for adults) is linked with an increased mortality risk. Oversleeping is also a common symptom of mental health disorders like depression.

Overall, studies consistently find minorities, especially black and Hispanic Americans, are less likely to experience “healthy” sleep (between 7 to 8 hours). They are significantly more likely to sleep too little, or too much.

Unfortunately, their sleep problems don’t stop there. The sleep they do have is less restful as well.

For example, a 2013 study of 164 adults found that African Americans spend 5 percent less time in deep sleep and more time in light sleep than white Americans.

Deep sleep is an important stage of sleep for our physical health, since it’s during this stage that our body restores and repairs itself from the strains of the day. Lack of deep sleep can impact how your body metabolizes glucose, which may eventually lead to type 2 diabetes, a condition which already disproportionately affects black and Hispanic Americans.

A 2010 study of nearly 10,000 individuals likewise found a strong relationship between income level, ethnicity, and sleep quality. African-American and Latino participants were over 50 percent more likely to experience poor sleep than white participants, and those below the poverty level were almost 3 times as likely to experience poor sleep than the wealthiest participants.

Another 2013 survey of over 4,000 individuals assessed how socioeconomic factors affected individual sleep issues, such as snoring or difficulty falling asleep. Key findings included:

• The people most likely to have a tough time falling asleep at night (taking 30 minutes or longer) were black, didn’t have private insurance, or experienced food insecurity (the last two of which are indicators of poverty).
• Food insecurity was additionally tied to difficulty staying asleep, awakening too early, or feeling unrefreshed from sleep.
• Snoring was more prevalent among individuals who identified as non-white Hispanic, had less education, or experienced food insecurity.

The CDC looked at how poverty affected sleep. When defining “poverty status,” the CDC looks at where your income lies in relation to the federal poverty threshold. At the time of the survey, the federal poverty threshold was $11,670 for a single-individual household and $23,850 for a four-person household.

As you can see, the likelihood of short sleep (sleeping fewer than 7 hours) increased with greater poverty:

Independent researchers have also found a correlation between better sleep and higher income levels.

In the graph below, the “1 income level” equates to $16,000 while “7 income level” represents those making over $100,000. Notably, lower income level participants spent more time in bed, but slept significantly less, suggesting that more of that time may be spent experiencing the kind of anxiety and worry that contributes to insomnia.

Similarly, employment status is also correlated with sleep quality. In the chart below, employed people represent the baseline, as they are the least likely to report sleep complaints. All forms of unemployment are highly associated with disturbed sleep, with those who are unable to work reporting the worst sleep of all:

The relationship between income and sleep works both ways. The higher your income, the better your sleep, according to a 2018 Harvard Business Review report.

Researchers surveyed 35,000 business leaders and found a correlation between sleep quantity and business role. The more senior their role, the more that person sleeps, with senior executives getting the most sleep of all. Considering that senior executives also tend to have extremely high household incomes, these results support the broader trend that financial security goes hand in hand with better sleep.

The problem with the sleep gap in America is that it’s a cyclical problem.  People who are lower-income, as well as people of color, must cope with a complex system of disadvantages. These hurdles, many interconnected, make it more difficult to achieve good sleep health.

We review these contributing factors in the sections below.

Less Time for Sleep

People who are poor typically work multiple jobs in order to make ends meet. When you’re working a day job and a night shift somewhere else, you simply have less time for sleep.

About 15 percent of the American workforce works multiple jobs. These people are 61 percent more likely to sleep fewer than 6 hours on a weeknight, since more of their time is spent working multiple jobs and commuting to them. These people are also more likely to have irregular work hours, begin work earlier and end it later than others, preventing them from following a regular sleep schedule.

Studies show that individuals who work multiple jobs also tend to have disrupted circadian rhythms, since they’re more likely to work longer and later at night. This increases their risk for on-the-job injury, and makes it tougher to fall asleep when they need to.

Plus, as gentrification continues to push lower-income individuals away from the center of the city – where the jobs are – their work is likely to be coupled with longer commutes. Even with public transportation, the farther you travel, the higher the cost to get to work, draining an already stretched low income.

The Link Between Sleep Deprivation and Poor Health

The CDC findings reveal that, on average, racial minorities are more likely to miss out on good sleep than white Americans. But how much sleep are they missing out on, exactly?

Black Americans get up to 1 hour less of total sleep per night, according to one study. In another study, the difference in sleep between black men and white women was 82 minutes. That’s a significant disparity, and the toll adds up quickly.

Long-term sleep deprivation, like that experienced by black and Hispanic Americans, is a risk factor for a number of health problems, notably obesity, diabetes, and cardiovascular disease.

The two most common sleep disorders are obstructive sleep apnea (OSA) and insomnia. Generally, they affect as much as 15 percent of the population. OSA is a sleep-related breathing disorder where the individual experiences temporary lapses in breathing during sleep, lowering their sleep quality and oxygen levels, while increasing stress and daytime sleepiness.

OSA is more than twice as prevalent in black Americans than white Americans. Hispanic and Chinese Americans are also more likely than white people to suffer from sleep-disordered breathing. Among children, black children are four to six times more likely than white children to have OSA.

Additionally, there is a strong comorbidity between OSA and hypertension, a condition which already disproportionately affects black Americans. Overall, 30 percent of individuals with hypertension suffer from OSA. For black Americans, that number skyrockets to 90 percent.

OSA is also tied to obesity and diabetes, which are often comorbid as well — and similarly pose a significantly higher risk for black and hispanic Americans. Black people are twice as likely to experience short sleep than white people, and short sleepers are 55 percent more likely to be obese.

The same circadian rhythms that control our sleep also regulate other hormones, including appetite hormones like ghrelin and leptin. When you get less sleep, or experience poorer quality sleep, ghrelin production kicks into overdrive, increasing appetite and leading to the weight gain that can cause obesity and diabetes.

Again and again, the research shows that minorities and those from lower socioeconomic groups have a higher risk of both sleep disturbances, and the health consequences that can develop from disturbed sleep. With better sleep, mental and physical health can improve — but for many minorities, achieving better sleep is an uphill challenge due to systemic barriers to equality.

Suboptimal Sleep Environments

Non-white people can experience a harder time finding better jobs and housing due to discrimination. Housing insecurity can lead to instability at home, which increases stress for all household members. Children are at particular risk, as a way out of poverty can be better education, but if a stressful home life is interfering with their sleep, they’re more likely to miss school, or experience impairments to their academic performance due to sleep deprivation.

Poorer neighborhoods also tend to be poorer environments for sleep. They’re typically crowded and more urban, which means more light pollution and noisier living quarters. An ideal bedroom environment is one that is cool, dark, and quiet – and noisy urban neighborhoods typically don’t fit the mark. Accordingly, individuals who experience poor sleep quality are also more likely to have poorer sleep environments (as measured by bonise or temperature).

However, one study monitored the sleep quality of adolescents living in an urban neighborhood. While most of them slept fewer than the recommended 9 hours, those of lower socioeconomic status had significantly worse sleep duration, quality, and consistency. So, if they are of high or medium socioeconomic status, people may be able to achieve better sleep — even if they are in an urban environment. A crowded household may be the stronger predictor of shorter sleep.

The impact of the home and sleep environment should not be discounted. One study moved participants from crowded slum housing in Buenos Aires into a basic modular home. After the move, both the sleep quality and overall quality of life drastically improved for the participants — leading the authors to conclude that even a “minimal improvement in the quality of basic housing can significantly increase sleep quality.”

Lower Education, Less Sleep

While it’s less of a one-to-one relationship than with household income, education level also appears to be related to sleep inequality. In some ways, this makes sense, as more education tends to correlate with higher household incomes (although not always).

According to one study, individuals with graduate-level degrees or higher are the most likely to enjoy healthy sleep. 70 percent of them sleep between 7 to 8 hours a night, with bachelor degree holders close behind at 67 percent. From there, it’s a big drop: fewer than 60 percent of people with an associate degree or less regularly get healthy sleep.

Other studies have observed similar findings. Those with less education tend to report more disturbed sleep. The chart below represents the odds ratio of sleep complaints by education level, with college graduates as a baseline. Those who completed high school or some college were between 1.2 and 1.3 times more likely to report disturbed sleep than college graduates, while those who didn’t graduate high school were between 1.35 and 1.65 times more likely to report disturbed sleep:

Another study charted the amount of sleep participants received over a period of 34 years. There was a clear relationship between the level of education completed, and the amount of sleep participants received on average. Those who didn’t graduate high school were 5 to 10 percent more likely to have short sleep:

Concerningly, the study noted that across the board, sleep duration decreased with time. This occurs naturally, as the neurons that regulate our sleep die off as we age.

However, the researchers observed that the probability of short sleep duration increased significantly more among African Americans and Hispanic Americans than it did in white Americans. Better living conditions and socioeconomic status had the strongest mediating effects on the disparity. This suggests, like many of the studies have, that the obstacles to sleep experienced by minorities are caused by larger systemic issues like gentrification, discrimination, and lack of access to better job, social, and educational opportunities.

Just as the research suggests the sleep disparity begins in childhood, so do its effects on academic success. A report from the American Psychological Association confirmed findings that children from lower socioeconomic status were more likely to have short sleep, poorer sleep quality, and less consistency in their sleep. They were also more likely to have sleep disorders.

Further, while students from lower and middle classes had similar performance when they were enjoying optimal sleep, if their sleep worsened, only the cognitive performance of the lower class children suffered. Worse, the researchers were able to chart the effects of poor sleep on their academic performance (and behavioral issues in school) two years later.

Sleep and Income Challenges Presented by Mental Health

People in a low-income household have a higher incidence of mental health concerns, paired with fewer resources to cope with these problems. This trend continues for people living in extreme poverty. Up to a third of the country’s homeless population suffers from severe mental illness — compared with only 4.5 percent of the general population.

Worse, when people are poor, they are less likely to receive treatment for their mental health. This could be due to a variety of things, including no free time to visit the doctor, a lack of insurance, or a general inability to pay. As a result, their mental health worsens, further interfering with their quality of life and their sleep.

The stressors of poverty can lead to mental health issues in the first place, such as anxiety and depression. In turn, mental health problems make it more challenging to perform optimally in school and work, which can continue the cycle of poverty.

Sleep problems are a common side effect of many mental health disorders, including anxiety, depression, and bipolar disorder. Disturbed sleep also increases your suicide risk.

Stress Levels Are on the Rise, Especially for Minority Americans

People living in poverty often experience food insecurity, housing insecurity, and job insecurity. If you are worried about being able to buy groceries for dinner tomorrow, paying your rent, or making it home safely, you’re living in a state of constant stress.

Stress activates your nervous system, making you feel alert, so when you do have time to sleep, it’s much harder to relax sufficiently in order to fall asleep. No surprise then, that people who feel they live in safer neighborhoods tend to report better sleep quality. Those who don’t, however, are more likely to suffer from stress, and sleep worse as a result.

The disparity in sleep between black and white Americans is stark. So is the disparity between their stress levels.

Worse, this disparity has grown in recent years. A recent study charted the effects on sleep among nearly 400,000 American adults between 2004 and 2017. They noted that overall, there has been a growing trend of Americans getting less sleep. They attributed this sea change to increased economic instability from the 2008 recession, social stress, and technology use (smartphone usage negatively impacts sleep).

Everyone is using smartphones more, but economic instability and social stress disproportionately affect minority Amercians — among whom the increase in short sleep was higher than in whites. The number of black and Hispanic Americans experiencing short sleep increased by almost 7 percentage points during this time period, compared with just 2 percentage points for white Americans.

Discrimination is another contributor to stress and predictor of poor mental health. In the study that found the differences in deep sleep among white and black Americans, participants were also surveyed about whether they felt they experienced discrimination due to their race or ethnicity. Those who felt they experienced more discrimination tended to be the ones who got less deep sleep.

Multiple studies have also documented the negative effect racial discrimination has on blood pressure. Increased blood pressure creates the overarousal that leads to insomnia and disrupted sleep quality.

Beyond its affect on stress leels, one study looked into whether racial discrimination alone could be an indpendent predictor for disturbed sleep. Using data from the 2006 Behavioral Risk Factor Surveillance System, they found that black Americans were nearly 7 times more likely to report racial discrimination when in a healthcare setting than white Americans. Experiencing racism was associated with a 2 to 2.6 times higher risk of daytime fatigue and disturbed sleep.

A recent 2019 study observed the effects of acculturation stress and discrimination among Hispanic populations in the U.S. Those suffering from more chronic stress were more likely to have trouble sleeping, with the effects even more pronounced among those who were unemployed. “The impact of acculturation stress on insomnia is stronger among Latina/os who aren’t working,” said Carmela Alcántara, PhD, lead author of the study. “They may spend more time in bed and ruminate, or take more naps during the day.”

The relationship between stress and poor sleep works both ways: the more stressed you are, the harder it is to sleep — and the less you sleep, the more stressed you feel.

Food Insecurity Contributes to Stress and Poor Health

Low-income households, particularly those living beneath the poverty line, can suffer from food insecurity. In 2018, 11 percent of Americans (or 14.3 million people) experienced periods when they were uncertain of their ability to access enough food for themselves or their family.

Research on the subject has shown that food insecurity is associated with a drop in sleep quality. This can appear as taking a long time to fall asleep, in addition to a lower amount of total sleep each night. Children are particularly vulnerable, with young children in food-insecure families showing poor sleep quality regardless of bedtime routines, amount of total sleep, or other factors.

Food insecurity can also tie into the issues influencing poor health and obesity, as people grappling with this problem have higher rates of type 2 diabetes and heart disease.

Just as your income level affects your sleep, it also affects the food you can afford — which in turn affects your sleep. Lower-quality diets, such as those composed of overly sugary, fatty, or otherwise junky foods, tend to result in lower-quality sleep.

Multiple studies have linked poverty level with worse health outcomes. Unfortunately, better food costs more, and it’s often more than those in poverty can manage.

The Impact of Poor Sleep on Parenting and Child Development

There are also non-health cyclical repercussions of worse sleep that result in further widening the inequality gap. For example, better sleep is a prerequisite for better parenting.

Like anyone, when parents get more sleep, they’re less stressed, more focused, and more emotionally stable. Without adequate sleep, their stress levels rise, their focus and memory are affected, and they become more emotionally volatile.

Stressed-out parents, whether they’re stressed from inadequate sleep or access to fewer socioeconomic resources (or both), have less time and patience to provide care to their children. They may not have the time to help their kids with their homework, and if they do have the time, they may find their mind wandering so they’re unable to be effective when solving tough math problems. Because their memory is affected, they may forget to pick up the kids from school. And with less emotional stability, they may be more prone to angry outbursts, which can worsen their relationship with their child.

These are all hypotheticals, of course, but they demonstrate the broader implications of getting poor sleep as a parent — and how it can lead to deeper disadvantages for their child.

And while these particular examples are hypotheticals, there is evidence of the connection between good sleep and parenting. A recent University of Illinois study found that mothers who are either sleep-deprived, or have longer sleep latency (difficulty falling asleep) are more likely to have permissive parenting styles — the academic term for parenting with lax or inconsistent discipline. In turn, that type of parenting style has been linked with an increased vulnerability among adolescents to engage in risky behaviors like skipping school or substance abuse.

“We found that when mothers were not receiving enough sleep, or receiving poor quality sleep, it had an effect on their levels of permissiveness with their adolescents,” said Dr. Kelly Tu, lead author of the study. “It may be that they’re more irritable, experiencing impaired attention, or so over-tired that they are less consistent in their parenting.”

Tu and her fellow researchers noted a correlation between the socioeconomic status and race of mothers in their study, and the impact poor sleep had on their parenting style. Like their non-minority peers, when African American mothers or those from lower socioeconomic households had better sleep, they were less likely to engage in permissive parenting. However, when they got worse sleep, they demonstrated higher levels of permissive parenting.

These findings are similar to the APA research we discussed earlier regarding the disproportionate impact of poor sleep on minority children. When children get better sleep, they experience favorable outcomes fairly equally, regardless of their race or socioeconomic status. But when minorities experience poor sleep, they suffer to a larger extent than their peers from white or higher socioeconomic status households.

“Studies have documented sleep disparities among ethnic minority and socioeconomically disadvantaged individuals, and our findings are consistent with that. For socioeconomic status, we may need to consider the day-to-day stressors or challenges that these mothers are facing,” acknowledged Tu. “Mothers from lower socioeconomic households may be encountering additional stressors or financial hardships that could be affecting their sleep and/or parenting.”

If people of color are systematically sleeping less because of systemic racism, this could influence their parenting and alter the life course of their children, creating further social inequality. If disadvantaged children are sleeping less, and consequently doing worse in school, their life course is also changed. Sleep is an incredibly important mechanism for producing and reproducing social inequality more broadly.

Sleep inequality is a serious issue because it creates a vicious cycle, wherein socioeconomic factors contribute to people getting poorer sleep, and then that poorer sleep makes it harder for them to overcome their socioeconomic disadvantages.

Regularly sleeping fewer than 7 hours leads to chronic sleep deprivation, which is linked with a variety of mental, emotional, and physical health consequences. People who are sleep-deprived are at increased risk for long-term health conditions, including obesity, diabetes, cancer, and cardiovascular disease. Many of these same health conditions are also more common among black and Hispanic populations.

One specific concern with socio-economic sleep inequality is the loss of REM sleep. This stage is concentrated in the latter half of the night, so when you cut your sleep short, you lose out on REM sleep most of all. It is also impacted by cortisol, a hormone produced during periods of stress.

During the REM stage, we dream and process information from the day. It plays a critical role in emotional processing, so that after a night without enough REM sleep we feel more emotionally volatile and less able to focus. People living with inequality are under a great deal of institutional stress, and the lack of REM sleep erodes their ability to cope with these stressors in a constructive way.

People who are sleep-deprived also experience impairments to their cognitive performance, affecting their ability to succeed at school and work.

For example, teenagers who are sleep-deprived experience academic set-backs in a variety of ways. This trend becomes compounded over time, as students who do poorly in school may then end up struggling with further situations — such as multiple jobs or shift work — which also cause disturbed sleep. This may be one reason for the difficulty in breaking the multigenerational cycle of poverty.

The effects of sleep deprivation are only one way that inequality can cause cognitive problems. Studies have also found that the stress of poverty itself can impede cognitive function, as people spend their mental energy focusing on poverty-related concerns. This, of course, further exacerbates (and is exacerbated by) the problems caused by poor sleep.

Clearly, sleep inequality is a complex problem. Inequality sets people up for poor sleep, and that poor sleep makes their lives even more difficult. Prior to these studies, we knew poverty, racism, and sleep deprivation were all issues affecting individual Americans. Now, we know that these issues in turn affect each other.