Whether shift work, high-performance careers, or the incessant appeals of infants, many of us just can’t get the sleep we want. So when a miraculous day off appears, the freedom to sleep in feels like the best thing that has ever happened.
Yet somehow, after ten, twelve, or even fifteen hours of sleep, we wake up groggy and still sleepy. The refreshment we craved has eluded us even after a bout of solid sleep. How can that be?
That’s the question posed by Wired science reporter Nick Stockton in his article “What’s Up With That: Why Does Sleeping In Just Make Me More Tired?”
Stockton explains that sleeping in upsets your body’s sense of time in the same way that quickly crossing time zones leads to jet lag. Your “biological clock” gets confused and your cells don’t know how much energy you need at what time. This part of the article makes sense.
He should’ve left it at that.
He then goes on to explain how sleep scientists have linked regular oversleep with health issues, specifically “diabetes, obesity, and even early death.” He lists a number of factors that could induce oversleeping, from alcohol and drugs to a lumpy bed that inhibits deep sleep, thereby causing you to feel tired for longer.
The article starts to leap from subject to subject with no transition or explanation. We start off with oversleeping being like jet lag, and then suddenly we are talking about regularly getting nine to eleven hours of sleep in a twenty-four-hour period (which is not like jet lag at all, since it’s regular). All at once, he turns to the subject of irregular sleep hours and how those who sleep in the day can trick their brains into thinking it’s nighttime. We are just getting our bearings when Stockton switches over to what happens during a sleep cycle and how to improve the overall quality of your sleep by changing your sleep situation. At this point, we try to catch our breath when he sprints over to discussing recognized disorders like sleep apnea and narcolepsy, one of which causes you to stop breathing in your sleep and the other which makes you fall asleep at inopportune times. He tenuously links these conditions to his topic with the line, “In addition to all the other terrifying aspects of this disease, it’s not doing your quality of sleep any favors.” We are far from the realm of oversleep at this point.
In the end, Stockton recalls his original point, advising readers to establish “some equilibrium between your weekend and weekday sleep.” Huh? Most of the article has nothing to do with this kind of imbalance and a lot of the health issues he presents don’t actually have anything to do with oversleeping.
Although a punchy, enjoyable writer in terms of style, Stockton doesn’t seem to know what his article is about. He never defines oversleep (is it sleeping more than you usually do or sleeping more than the social or scientific norm?). He answers the question in his title in the first four paragraphs and then takes a nosedive into a bunch of tangentially related material.
He also sets up an artificial causality not present in the scientific studies he cites. Although cliche, we have to remember the famous statistics phrase: Correlation does not imply causation.
Just because memory loss or diabetes is more common in people who sleep more than is scientifically accepted as normal in this part of the world, we can’t assume that the relationship between a health condition and sleep is unidirectional. In fact, one study he cites from Harvard makes it explicitly clear that the jury is still out on how any of this works:
“Another possibility is a two-way street between sleep and memory: sleep quality may affect memory and thinking, and the brain changes that cause memory and thinking problems may disturb sleep.”
I’m not arguing that sleep has no impact on health. However, popular science writers like Stockton tend to ignore other possibilities. Their presentation style, if not their actual arguments, suggest that what they say is an absolute fact. But maybe people who work a lot have diabetes because they don’t eat well, not because of their sleep. Perhaps someone who chronically “oversleeps” (whatever that means – we still don’t know) has some other condition that leads to both longer sleep duration and earlier death.
Nobody knows. Scientists don’t know, and they will be the first to tell you that sleep studies are still in their infancy. The world has only had the technology and social conditions to study sleep objectively since around the mid-twentieth century (see, for example, Kenton Kroker, The Sleep of Others and the Transformations of Sleep Research, 2007).
It’s no wonder we’re still confused.
So instead of pretending we have all the answers, let’s allow ourselves to live with our lack of knowledge. And let’s cut the muddled pop science articles trying to create coherence out of limited scientific evidence.