Sleep research reveals keys to health
By Lydialyle Gibson, excerpted from The University of Chicago Magazine
Photo courtesy of University of Chicago Medicine
If you sleep deprive an individual, basically nothing remains normal, whether mental or physical. Sleep is a basic need for function at every level.”
—Eve Van Cauter
UChicago Sleep, Metabolism, & Health Center
“I feel like a lab rat,” says Ruben Rodriguez. He looks a little beleaguered, smiling up from the bed where soon he’ll be asleep, while next door, a sleep tech will spend long, small hours monitoring his breathing and brain activity, his eye movements and muscle tone, the oxygen and carbon dioxide levels in his blood.
Covered head to foot in wires and electrodes, he is spending his fourth night in as many months at the University of Chicago Medicine’s Sleep Disorders Center as part of a study on obesity hypoventilation syndrome. Also called Pickwickian syndrome—in The Pickwick Papers, Dickens described a character with the classic symptoms—the disease usually combines severe sleep apnea with shallow waking respiration. “To the point where they’re not breathing enough to get rid of the carbon dioxide, so it accumulates in their bodies,” says Babak Mokhlesi, who directs the Sleep Disorders Center. “This is the extreme of the extreme.”
Rodriguez, 39, knew he’d put on a lot of weight in the past few years—he reached 375 pounds before he started working it off this past January—and he was waking up frequently at night. A driver for a handicap-accessible van service, Rodriguez kept nodding off at the wheel when traffic slowed to a stop. “I never hit nobody, thank God,” he says.
Going in for a diagnostic sleep study last fall, he found out that when he slept, his breathing periodically stopped for 20 seconds at a time, sometimes longer, before his brain lurched into action, sending an urgent signal for him to rouse up and gasp for air. (“Apnea” comes from a Greek word meaning “without breath.”) In the course of a night, this might happen dozens of times.
Tonight is Rodriguez’s last in the sleep lab. Now outfitted with a CPAP device (the acronym stands for “continuous positive airway pressure”) that keeps him breathing normally through a mask that fits over his face, he sleeps soundly, solidly. Five minutes after sleep tech Greg Bild wishes him goodnight over the intercom, Rodriguez is asleep. A little more than an hour later, he’s in REM, the digital waves that track his eye movements picking up speed, rolling over each other as they undulate across the computer screen’s teeming, black cosmos.
The University of Chicago has a long history with sleep. “I heard this was the place where they invented it,” Rodriguez joked the first time he came to the medical center. That’s not quite true, but it is the place where sleep science first took shape, beginning in 1925, when Chicago physiologist Nathaniel Kleitman, PhD’23, established the world’s first sleep lab on the second floor of Abbott Hall. UChicago scholars became leading sleep researchers, documenting breakthroughs such as the discovery of REM sleep, the origins of narcolepsy, and produced some of the first research on insomnia and sleep apnea.
Nearly a century later, the mysteries of sleep remain profound. Sleep researchers converge from across disciplines: physicians, neuroscientists, psychologists, and physiologists. As David Gozal, who leads UChicago’s pediatric sleep program, says, “The universe of sleep here is expanding. There are lots of galaxies out there.”
Most of those galaxies exist within UChicago Medicine, but some are farther flung. Social neuroscientist John Cacioppo has shown that loneliness can damage sleep quality, and biophysicist David Biron searches for clues to the genetic mechanism that regulates sleep in the “lethargus” behavior of roundworm C. elegans, a tiny primitive organism whose quiescent state resembles our own.
For more than a decade, organismal biologist Daniel Margoliash and psychologist Howard Nusbaum have investigated how sleep affects cognition in people and birds. Margoliash and Nusbaum have shown that sleep consolidates and protects new memories, and can even restore memories that seem to be lost.
Most of the University’s sleep research, though, happens within the medical center, where the past two decades of discovery have leaned more toward the physiological than the psychological: how sleep—or lack of it—interacts with obesity, diabetes risk, hormone function, metabolism, and cardiovascular problems. In 2008 scientists led by epidemiologist Diane Lauderdale, AM’79, AM’81, were among the first to draw a conclusive connection to heart disease. In a novel study this past January, internist Vineet Arora, AM’03, examined how hospital noise, which sometimes spikes to a chainsaw-loud 80 decibels, disrupts patients’ rest, and perhaps with it their recovery.
“We have developed a theme that basically could be summarized as: the importance of sleep for physical health,” says Eve Van Cauter, who directs the University’s Sleep, Metabolism, and Health Center. “I mean, your grandmother would say, ‘I knew it all along, that sleep is important to stay healthy.’” Study by study, sleep researchers are proving it.
In 1999 Van Cauter published a groundbreaking report in which she found chronic sleep loss alters hormone secretion in young, healthy adults. In some subjects who were sleeping only four hours a night, glucose metabolism came to resemble that of diabetics. Their blood cortisol rose to levels usually seen in much older people. The study was one of the first to explore the effects of sleeplessness on the body rather than the brain.
Since then Van Cauter’s research has linked poor, irregular sleep to a multitude of chronic diseases: diabetes, obesity, and heart disease. She has studied shift workers and jetlag sufferers. Last year she and biomedical anthropologist Kristen Knutson reported that insomnia can worsen insulin resistance in diabetics. In another 2011 study, Van Cauter found that sleep loss can lower young men’s testosterone levels. Sleep apnea, she’s reported, can raise the risk and severity of diabetes.
“Many of my colleagues in the sleep field will say that the function of sleep is still unknown,” Van Cauter says. “‘Why do we sleep?’” But the question, she argues, is itself a fallacy: there’s no single function. “If you sleep deprive an individual, basically nothing remains normal, whether mental or physical. Sleep is a basic need for function at every level.”
Also at the University of Chicago Medicine, Nanduri Prabhakar is trying to solve the pharmacology for obstructive sleep apnea, which happens when the soft tissue around the airway blocks off breathing. Pediatric pulmonologist David Gozal examines the effects of disrupted sleep on children’s brains and bodies — children with the poorest and shortest sleep were four times more likely to be obese, and their blood tests showed increased metabolic and cardiovascular risk factors.
Just down the hall from the bed where Rodriguez is spending his final night in the sleep lab, a three-year-old girl struggles to get to sleep. She’s come in for diagnosis and treatment of a nighttime breathing disruption—the sleep techs suspect sleep apnea—and for two hours she whimpers and squirms before she drifts off, long after midnight.
Sleep disorders have genetic and biological underpinnings that researchers are just beginning to understand, but lack of sleep is also often environmental, and often in ways that are not within people’s control: Life’s responsibilities push back bedtimes. Stress keeps people awake. Children sleep irregularly because their parents do.
There’s also something Gozal might call a modern lack of regard for sleep. “You look at the earth today,” he says. “It’s all light, all noise. The quality of our sleep, the regularity of sleep—it has disappeared.” People ignore the effects of sleep loss because they can. “It’s the only thing that doesn’t punish you immediately.”
But sleeplessness does punish you. “Every aspect of our lives essentially revolves around sleep,” Gozal says. “It is the dark matter that connects all the visible stars.”