05 Sep, 2017 The benefits of napping
By Doug Williams
It’s 3 p.m. and your head feels stuffed with cotton. You’ve been at work all day and your eyelids are heavy. You can’t concentrate. Your only wish is to crawl over to the sunny spot on the office floor and be a cat for 30 minutes.
Dr. Sara Mednick says people should listen to their inner feline.
“A 20-minute nap or an hour-long nap can save your life,” she says.
Mednick has studied napping since 2001 and is the author of “Take a Nap! Change Your Life,” published in 2006. She is a sleep researcher and assistant professor of psychology at UC Riverside, where her lab work focuses on the benefits of napping for improved memory and functioning. Previously, she was at UC San Diego.
“I don’t try to tell anyone what to do, but I definitely try to give them some ammunition for saying there is a way out of the continuous caffeine cycle where you just drink caffeine all day and then you don’t sleep well at night and then you need more caffeine the next day,” she says. “And, showing also that caffeine doesn’t always show the kind of cognitive benefits that people think (it does). We’ve actually shown it can decrease cognitive benefits compared to napping.”
Employee napping has been embraced by high-profile companies such as Google, Uber, Zappos and PricewaterhouseCoopers. All allow employees to blend naps into their schedules. Some provide quiet rooms and “sleeping pods.”
The National Sleep Foundation has said a nap can restore alertness, enhance performance and reduce mistakes and accidents. It also cites a NASA study that found a 40-minute nap greatly improved the performance and alertness of military pilots and astronauts.
“I think more and more people are realizing that they shouldn’t feel so bad about it and they should engage in the habit,” says Mednick.
Pros and cons
Lack of sleep can cause a number of problems, says Dr. Atul Malhotra, the director of sleep medicine and division chief for pulmonary, critical care and sleep medicine for UC San Diego Health.
Malhotra says most people need seven to nine hours of sleep per day (24-hour period), and if they come up short, it can result in neurocognitive deficits (memory, concentration, creativity, attention) and cardiometabolic risks (heart disease, weight gain, diabetes).
That’s why it’s important for those who don’t get enough sleep at night to try to make up for it during the day. As long as a person gets into that seven- to nine-hour daily range — even if it’s a combination of night and day sleep — they should be fine, he says.
About a third of Americans take naps, according to the National Sleep Foundation. But Malhotra says adult napping isn’t a one-size-fits-all issue.
“If somebody asks me as a sleep expert should you go to bed to nap, my answer is it depends,” he says. “If you’re napping because you’re not sleeping enough at night, then I recommend you sleep more at night. Are you napping because you can’t breathe at night? Then I recommend you see a doctor and get your sleep apnea treated.
“Are you napping because you like to and there’s nothing else wrong? Then that’s your lifestyle and your preference, and that’s fine. Are you napping because you have insomnia? Then I really recommend you avoid naps, because if you can’t sleep at night, then a nap during the day can make it worse.”
Malhotra also says naps are helpful to bank sleep before having to stay up late. But he says naps aren’t for everyone, including those with insomnia and “sleep inertia.”
“(They) fall asleep and then it takes them longer to wake up and they’re just not … they’re groggy and it takes them a while. If you’re one of those and you know you have to drive somewhere at 3 p.m., best not to take a nap and wake up at 2:50 p.m. and then be groggy and get into a car. Those people have sleep inertia.”
Mednick, in fact, says there are nappers (those who can easily fall asleep during the day and get benefits) and non-nappers (those who have trouble getting to sleep and have a hard time coming out of deeper sleep.). It’s not known why some people are nappers, but she believes it’s likely genetic.
She says nappers — about 50 percent of the population — can get benefits from a quick afternoon nap, even if they’ve had seven to nine hours of sleep the night before.
“It helps them and they really love it,” she says. “They’re the type of people that go do exercise because they feel good about it. They take a nap because they feel good about it.”
At her lab at UC Riverside, often sleep-deprived students go through various tests to study the impacts of naps. Those who reach pre-REM (rapid-eye movement) levels of slow-wave sleep — and are awakened for tests — experience benefits to memory. Nappers often have the ability to wake easily from a short rest before reaching the deeper REM level.
It’s for these people who can easily slip into and out of sleep that afternoon catnaps are a gift. So when the sun comes streaming in at 3 p.m., it’s only natural they want to curl up somewhere quiet.
The late-afternoon lull for our bodies is a real thing, and Mednick calls it a “midday dip” in which body temperatures and cognition decrease.
“This is a prime opportunity and historically has always been a time when people slept more,” she says. “So the argument that people should just sleep more (at night) and they don’t need daytime sleep, it doesn’t really go with history. Historically, people have napped.”
This article was originally published in The San Diego Union-Tribune.