I like to tell people I am a world champion sleeper. I fall asleep fast, I stay asleep long, and I have a vibrant dream life. Yes, you are probably jealous.
But what I also now know, after using a Fitbit to track my sleep for the last six weeks, is that I don’t sleep deeply. In fact, last night, though I slept 8 hours and 55 minutes, only 33 minutes of that was spent in a deep sleep — the kind of sleep that rebuilds and repairs cells. That seems worrisome.
According to Dr. Michael Grandner, director of the Sleep and Health Research Program at the University of Arizona in Tucson and a Fitbit sleep consultant, “deep sleep is very much about the body.” He is quoted on the company’s blog saying that during deep sleep, “the thinking parts of the brain are largely offline. Your muscles are very relaxed. You’re not dreaming at all during this time. Your body is doing a lot of rebuilding and repairing.”
Deep sleep has also been linked to immune function and memory.
In December 2017, NPR reported on a study that suggests that memory loss in older adults may be linked to poor coordination between brain waves in deep sleep. The researchers found a likely reason for the lack of brave wave coordination: The normal aging process results in atrophy of an area of the brain involved in producing deep sleep. In other words, as we age, we get less deep sleep — and the deep sleep we do get can be faulty.
Since few adults observe the bedtime recommended for a third-grader, it’s not surprising that half of women ages 40 to 59 report waking up feeling like they aren’t well-rested more than half the week.
What’s more, a January 2018 story by Reuters reported on the results of four Swedish studies that concluded that “people who suffered from nightmares and insomnia in middle age were more likely to experience cognitive impairment in old age than people who slept just fine earlier on.”
Even before I purchased a fitness tracker, I suspected that I don’t sleep deeply, a condition that stems from a childhood spent in fight-or-flight mode. As a method of survival, I trained myself to stay semiconscious through the night. That behavior has proven impossible to alter even as an adult who no longer worries about doors without locks. My Fitbit experiment confirms that I sleep long but light — almost always engaging part of my brain in keeping watch.
Most people buy the device, which you wear on your wrist, to track their activity level — aiming for 10,000 steps per day. But it also monitors sleep, syncing with an app on your phone to give you an analysis of the previous night’s sleep each morning. Along with my coffee, I enjoy charts and graphs that inform me about my light sleep, deep sleep, REM sleep, and awake time. (The company does a great job of explaining the purpose of each stage on its blog.)
My Fitbit sleep analysis reveals that in the last 30 days I spent just 8 percent of my sleeping time in a deep sleep, which is well below the average of 12 to 18 percent for women my age. But I spent 69 percent of my time in a light sleep. The average amount of light sleep for women my age is 40 to 60 percent. I was also awake 13 percent of the night, which is within the average range of 10 to 20 percent.
Even with all that time spent restless, I get 7 to 9 hours of sleep each night. The Centers for Disease Control and Prevention recommends that adults get at least 7 hours. I go to bed at an embarrassingly early hour. According to Fitbit’s data, Gen Xers who use the device typically go to sleep at 11:22 p.m. I go to sleep around 8 p.m. (I almost always get up at around 5 a.m., even on weekends, without an alarm.) Since few adults observe the bedtime recommended for a third-grader, it’s not surprising that half of women ages 40 to 59 report feeling like they aren’t well-rested more than half the week. This also seems worrisome.
It’s been a decade since the National Sleep Foundation studied women specifically, but I suspect not much has changed since 2007, when the foundation reported that 29 percent of women said they almost never sleep well at night. It also reported that 26 percent of perimenopausal and postmenopausal women take at least two naps each week. I hope these are the same people, because the perils of poor sleep for women in middle life are many.
“Insufficient sleep will exacerbate other issues associated with menopause, including mood disturbance and weight gain,” according to Natalie Dautovich, assistant professor of counseling psychology at Virginia Commonwealth University and Environmental Fellow at the National Sleep Foundation, whom CNN interviewed on the matter last year. And according to the American Heart Association, sleep deprivation and poor-quality sleep are linked to the inflammation associated with cardiovascular disease and stroke. Insomnia can raise your blood pressure and your risk for a heart attack.
The organization stresses that high-quality sleep is as important to health as diet and exercise. I suggest we all go to bed early tonight.