Tired after lunch or by mid-afternoon? You might think that you should go buy yourself some coffee. But according to UCSD researcher Sara Mednick, you’re better off taking a nap.
Mednick, a faculty member in the department of psychiatry at the School of Medicine, has been researching napping since graduate school and recently published a book, titled “Take a Nap! Change Your Life.” She talked about her findings Tuesday at UCSD’s Biomedical Library.
Nappers make fewer mistakes, are in a better mood and in better health, she said. “It also feels good,” she added. “And what’s wrong with that?” Napping also is important because many of us today say they have trouble sleeping, Mednick said. According to the National Sleep Foundation, about 40 percent of Americans report that they sleep less than seven hours a night – as opposed to the recommended eight hours. Everyone is affected, from infants to older adults, the researcher said.
And Americans aren’t just cranky because they don’t sleep enough, she added. They face higher risks for health problems such as diabetes, heart disease and depression. They’re also more likely to get into car crashes and other accidents, Mednick said.
She added she believes those who say their schedules are too full to fit in a longer night’s sleep. A good nap is the solution to their problems, said Mednick, who has spent quite a bit of time documenting the benefits of napping.
Some of her most striking research looks at napping compared to drinking caffeine. In one study, Mednick had one group of subjects nap for 90 minutes, while another drank 200 mg of caffeine. She also set up a control group, who took a placebo. Then she tested her subjects on several tasks, including typing and spatial skills, such as remembering the layout of a room or a map. On both tasks, coffee drinkers performed much worse than the placebo group, Mednick said. “Of course, this is a bummer for Starbucks,” she added.
Mednick started looking into napping when she was a self-described sleep-deprived graduate student at Harvard. She was inspired by stories of great, smart nappers, such as Bill Clinton and Leonardo da Vinci. At the time, there wasn’t much research about the cognitive benefits of napping. So Mednick set out to test subjects’ cognitive abilities with and without a nap. She found that her subjects’ performance increased if they napped and decreased if they didn’t.
Finally, one day, she decided to take her own advice. She went into a colleague’s office and took a nap on his couch. She woke up an hour later, feeling wonderful. Soon, her entire lab started using the couch, much to her colleague’s annoyance. It was finally moved to a windowless room and members of Mednick’s lab started napping in shifts, including pregnant women, a young father and a night owl who liked to work late into the night. “Everyone knew about the results and felt well defended that they needed to nap,” the researcher said.
That’s not to say that all naps are created equal. It all depends on which stages of sleep you’re going through, Mednick explained. The three most important stages are Stage 1, known as rapid-eye movement, or REM, and Stages 3 and 4, known as slow-wave sleep, when the brain is moving at a slower pace. Mednick and her colleagues set out to study how the different stages of sleep impacted subjects’ performance on tests after a nap. When they only got slow-wave sleep, their performance remained stable. But when their naps included REM and slow-wave sleep, it improved. A nap that includes equal parts of slow-wave sleep and REM sleep is the perfect nap, she added.
“The more you nap and the better you sleep, the better you do,” Mednick said.
After the talk, Tracie Davee, an assistant dean of student affairs at Warren College, said Mednick’s findings about coffee didn’t come as a surprise. She became a coffee fanatic in graduate school, but then realized she felt better when she drank decaf, she said.
Grace Bagunu, also a staff member at Warren, said Mednick had provided the scientific facts to validate what her body has been telling her for a long time. She gets really tired around 3 p.m., she said. She pledged to try and take a nap, albeit for just 15 minutes.