The effects of racism may seep into our brains and harm us even when we are trying to sleep, according to alarming new research that shows racial stress and discrimination cause Black adolescents and adults to get an average of a half hour less sleep per night than white people, which has an enormous impact on Black health and performance.
Social media users have frequently joked that they wished to get some of that “good white woman’s sleep”—who knew that all along it was actually true?
Researcher Emma Adam from Northwestern University has discovered that young adults from racial/ethnic minority groups who experience more discrimination have higher levels of cortisol in the evening, and less decline in cortisol levels throughout the day, than those with lower discrimination. Flatter cortisol rhythms across the day have been linked to a long list of problems, such as higher fatigue, poor mental health, cardiovascular disease and failing memory.
Using data collected over a 20-year period, researchers found that over time the more discrimination people experience across adolescence and early adulthood, the more dysregulated their cortisol rhythms are by age 32.
This is a devastating finding that should be heeded by all parents—frequent encounters with discrimination during adolescence affected the cortisol levels individuals had as adults.
One of the most significant impacts of dysregulated cortisol levels was on sleep.
Black people sleep less than white people, on average by just over a half hour per night for both adolescents and adults. Black people also get lower amounts of restorative deep sleep. Adam’s research attributes this to racial discrimination and the increased vigilance it causes—affecting sleep hours, sleep quality, and sleep architecture (the structure and pattern of sleep).
Other studies have found similar differences between Black and white sleep. One study found that white people were found to get an average of 7.4 hours of sleep per night, while Hispanics and Asians averaged 6.9 hours and Blacks 6.8 hours. In addition, sleep quality—which the study defined as ease in falling asleep and length of uninterrupted sleep—was also higher for whites than for Blacks.
Because of the importance of sleep to the human body and its optimal level of importance, this significant difference in sleep quality means that over time Black people are much more susceptible to greater fatigue, lower self-esteem, increased depression, disruptions in immune functioning, increased inflammation, increased obesity, diabetes and heart problems, increased risk of unsafe driving and accidents, slowed reaction times, and impaired attention and memory.
Even more troubling, the effects of discrimination on stress hormones may be passed down across generations, as researchers have discovered higher racial discrimination was linked to higher evening cortisol in pregnant mothers, and also predicted larger cortisol reactions to stress in the infants of those mothers.
All in all, this research is a potentially devastating finding that speaks volumes about the challenges Black people face in white-dominated societies.