The effects of it on your body and brain
In 1965, the 17-year-old high‑school student Randy Gardner slept not a wink for 264 hours, or 11 days, to find out how he would fare deprived of sleep. On the second day, his eyes lost their power of focus. Then he began to lose the ability to identify objects by touch. The third day saw him growing querulous and uncoordinated. At the end of the experiment, he was unable to concentrate. His short-term memory had become unreliable. He began to feel paranoid and hallucinated. Though Gardner eventually recovered with no measurable psychological or physical residue of his self-imposed ordeal, one person’s loss of sleep for a week can pose challenges for others — from hormonal imbalance to illness and, in extreme circumstances, actual death.
We’re only just starting to understand why we sleep in the first place, but we do know we need to. On average, adults require around seven or eight hours per night, while adolescents need a full 10. First, sensory messages wear our body out from the inside, sending messages to the brain to help us relax. Then, evaluating the sensory messages from our surroundings — it’s dark here — our brain responds with a cocktail of chemicals that induces a light doze that gets progressively deeper. For a couple of hours, breathing slows, the heart rate tumbles, muscle tone dissipates, and REM kicks in — the most frenetic of the sleep phases. REM and the quieter non-REM sleep propel a series of repair and restoration processes key to the balanced well-being and growth of our bodies and minds.
One in three adults and two in three adolescents in the US are chronically sleep-deprived. Staying awake isn’t just an annoyance; it literally kills you dead. When we get less shuteye, we can’t retain information, remember what we learned, behave appropriately, or function with the same dexterity. Sleep deprivation induces inflammation, hallucinations, and hypertension, and it has even doubled the risk of diabetes and obesity.
Yet in 2014, a hard-core football fan keeled over dead shortly after watching the World Cup game — an event that had kept him awake for 48 straight hours. But his untimely end — he died of a stroke — was probably a result of a bigger culprit: study after study has documented the dangers of sleeping less than six hours a night, with chronically shortened sleep found to raise the specter of strokes by a whopping four and a half times more than those who consistently get a regular seven to eight hours of shuteye a night.
For a few people in the world who bear an apparently single inherited genetic mutation, sleeplessness is a nightly reality; they suffer from Fatal Familial Insomnia, a syndrome in which the body is placed permanently in a state of horrifying waking. After months or years in which the condition worsens relentlessly, the sleepless misery culminates in dementia and death.
What exactly is it about sleep deprivation that makes it so miserable? The answer, according to many scientists, is that waste products amass in the brain over time. During our waking hours, our cells work hard to expend the energy sources we acquired during the night, which are slowly broken down into a range of byproducts, including adenosine. As the concentration of adenosine increases, it increases the pressure to sleep — or, as it’s more technically known, the feeling of sleep pressure. After all, coffee works its stimulating magic by blocking adenosine’s receptor cascades. Other kinds of trash accumulate, and if this waste isn’t cleared away, it all builds up. Eventually, scientists believe, these compounds overload the brain, causing all of the negative consequences of sleep deprivation.
Yet without the sleep effect, this buildup should be gumming up our grey matter. So what goes on in our brain to prevent this when we sleep? In 2012, a team of researchers identified a striking clean-up mechanism, aptly dubbed the glymphatic system. The mechanism doubles in activity overnight and clears toxic by-products — previously accumulated between cells — using cerebrospinal fluid as a flushing medium. New findings further suggest a role for lymphatic vessels, the pathways for our immune cells, in clearing the brain’s small molecules. Both of these systems deal exclusively with the brain’s daily chore of clearing out trash. While the restorative mechanism of sleep remains elusive, we know that if we want to remain healthy — and sane — we have to sleep.