Feinsilver said the notion that a person can “catch up” on lost sleep is misconstrued. “If you’re getting five hours of sleep Monday through Friday, by Friday, you owe yourself like, 10 or 12 hours of sleep,” he said. “It’s not quite that simple. What that means is that, in order for you to catch up on weekends, you’d have to sleep ridiculous hours. And nobody does. You’d have to sleep the seven, plus an extra 12.”
A sleep-deprived person recovers from sleep loss similar to a traveller recovering from a flight; she spends a certain amount of time tiring out her body and can rehabilitate with an equivalent or duplicative amount of recovery time. For each hour spent in a plane, a person needs approximately the same number of days to fully recover from jetlag. In a widely cited paper from 2006, European researchers compared this process to the body’s method of loss and recovery when it chronically loses sleep. The problem, the researchers write, is that many people who chronically lose sleep live in societies where their work and school schedules are not aligned with the body’s circadian rhythms. So they never make up for lost sleep from the nights before, and build up a “sleep debt” that is never repaid. The consequence of chronic sleep debt, they say, is “social jetlag”—a chronic slowing of concentration and hampering of bodily systems. Researchers like Feinsilver and Walseban fear that this affect has been widespread. “We’re a sleep deprived society,” Feinsilver said.
Feinsilver’s memory of the talking pumpkin stayed with him, but he did not decide to pursue sleep research until he won a fellowship to study the ventilatory drive, the mechanism by which the brain sends signals to the lungs and makes a person breathe. At the time, he said, people erroneously thought that sleep apnea was caused by problems with those signals. The research gripped him enough that that he decided to open his own sleep lab. Today, although his focus remains on sleep problems associated with breathing and the lungs, he continues to investigate the other negative effects that sleep deprivation has on the mind and body.
“Definitely, we know that sleep deprivation leads to depression, high blood pressure, weight gain, heart disease, and probably mortality,” he said. People that regularly sleep those seven and a quarter hours have been shown to live longer than those who routinely sleep less or more. He added that lack of sleep disrupts other systems in the body.
“For instance, if you stay up until 3 a.m., you might get very cold,” he said, clarifying that sleep helps to regulate your body temperature. “Your G.I. tract can get messed up. You’re not supposed to eat at three in the morning. It’s a fairly miserable experience.”
Both Feinsilver and Walseben, whose background is in biopsychology, said that these interruptions, as well as the aforementioned neurotransmitter disturbances, can disrupt reaction times and concentration. Walseben noted that certain famous historical accidents—such as the the spill of the Exxon Valdez oil tanker—were caused by sleep deprived workers. More recently, a Metro North train in New York may have derailed when a sleep-deprived engineer nodded off at the helm. Feinsilver said that lack of sleep is also a leading cause of automobile accidents, mainly because when the brain is deprived of sleep, it becomes particularly difficult to perform prolonged, repetitive tasks like driving.
While a person sleeps, her cells undergo a cycle of repair that provides both oxygen and glucose. When a person stays up all night, the brain’s cells are denied the products of this cycle, severely hampering the organs’ reactions to stimuli and instructions. “Every cell in our body needs food and it produces waste, so all those things occur in a regular, regimented way when we’ve slept well. And when we interfere with that, systems go out of sync,” Walseben said.
Feinsilver said that while we sleep, the blood stream is cleared of a substance that researchers call “substance S.” Many believe substance S is adenosine, a byproduct of energy production that cells release into the blood throughout waking hours. He said that without sleep, the blood gets clogged with substance S, slowing a person down from head to toe.
“It looks like there’s a toxic substance building up in you, where the more you’re awake, the more you see this stuff floating around the bloodstream, and the only way to get rid of it is to sleep,” he said.
While I was awake in Europe, my reaction time was horribly off and my ability to concentrate fell apart, and I became increasingly clumsy and weak. Today, I still feel like I have more difficulty concentrating than I did beforehand. It might just be my imagination. I will probably never be sure.
Many sleep researchers study people who have partial sleep deprivation. These subjects have social jetlag; in a typical sleep lab, they might sleep four hours or so every night for one week. But the experts I interviewed said that less is known about total sleep deprivation and its lasting impacts because researchers have moral concerns about forcing people to stay awake.
“Once you are up all night, by mid-afternoon, it becomes unbearable,” Feinsilver said. “You can do it, but it’s really torture.”
“You know what people might be doing that?” he added. “The army.”
A 2007 report on American torture tactics—written by non-governmental organizations Physicians for Human Rights and Human Rights First—has a section on sleep deprivation that begins with descriptions of a Soviet gulag. In The Gulag Archipelago, Alexandr Solzhenitsyn lists sleeplessness as one of 31 methods that his captors used to break a prisoner’s will. “Sleeplessness befogs the reason, undermines the will, and the human being ceases to be himself, to be his own ‘I,’” Solzhenitsyn writes. He says that guards in the gulag kept prisoners awake for up to five days by perpetually standing them up or by kicking them when their eyes drooped. The author quotes an inmate who endured this, listing his many symptoms, including chills, eyes “dried out as if someone were holding a red-hot iron in front of them,” a swollen and prickling tongue and a throat racked with spasms. “Sleeplessness was a great form of torture: it left no visible marks and could not provide grounds for complaint even if an inspection—something unheard of anyway—were to strike on the morrow,” Solzhenitsyn writes.
Because sleep deprivation “leaves no marks” and is believed to break a detainee’s will, across the world, the tactic has been adopted by government and security forces, notably by Chilean dictator Augusto Pinochet in the 1970s. Most notoriously, sleep deprivation has been used on several prisoners at the United States’ Guantánamo Bay prison camp in Cuba.