Minor sleep loss may have same effect as complete sleep deprivation, scientists say

The annual daylight saving ritual has passed and it serves yet again to remind us how precious our sleep truly is. Or at least most of us will admit to how hard it hits to lose an hour of regularly scheduled snooze time.

We probably all know at least one person who swears they go unbothered. That they function just fine on five or six hours. No big deal. Maybe that person is you. Not to rain on anyone’s “I’m a superhuman” parade, but the science disagrees.

Sleep science is an ever-developing field and there is no exact scientific consensus as to why we need sleep, but there is plenty of evidence documenting all the terrible things that happen when you don’t get enough of it. And you may be surprised how little sleep deprivation is required.

In 1985, American sleep researchers David F. Dinges and John W. Powell published a study that helped popularize the psychomotor vigilance test to measure the effects of sleep deprivation on reaction time. Participants were asked to watch a dark computer screen for 10 minutes and press a button as quickly as they could in response to seeing a light appear on a screen. The lights appeared at random, and each reaction was measured.

The participants were divided into four groups. One group was deprived of sleep for 72 hours, one group was restricted to four hours of sleep per night, another group restricted to six hours per night, and the one lucky group was allowed eight hours of sleep per night.

All sleep -deprived groups showed slowed reaction times, as to be expected. What was more interesting were the tests that showed participants sometimes failed to respond at all. This lack of response has become known as a microsleep.

A microsleep isn’t some new biohack. It’s a period of involuntary shutdown where you lose all external perception for a few seconds, usually without ever knowing. During these periods, you can look awake or appear to have nodded off. Either way, your brain waves slow down and you become unresponsive.

Over the course of the two-week study, those who got eight hours every night maintained nearly perfect performance. Those who pulled all-nighters had a 400% increase in missed responses after the first night, and that percentage escalated over the remaining two nights of no sleep.

Those with partial sleep deprivation fared better – for a little while. After six consecutive nights of four-hour sleep, participants had the same 400% increase in missed responses as those who had stayed up for 24 hours straight. After 11 days, their performance matched that of someone who had stayed up for 48 hours straight.

Then there were the folks who got six hours of sleep per night – an amount of sleep that is by no means out of the norm. After 10 days, their performance was the same as those who had stayed up for 24 hours straight. And like the other groups, performance deterioration continued to build over time.

Throughout the study, participants were asked about their perceived sense of performance impairment due to the restricted sleep. They regularly underestimated the effects, indicating that it is very possible to simply become accustomed to a state of sleep deficiency.

The Inland Northwest is lucky to be a hub of local sleep research, thanks to Washington State University’s Sleep and Performance Research Center. Marian Wilson, associate professor and core faculty member at the center, affirms that Dinges and Powell’s findings have held true.

“Most of our studies confirm that there is a discrepancy between sleep tracking devices and how well people think they are sleeping,” Wilson said.

To add to the mass underestimation of how well rested we are, sleep scientists have found that you don’t even have to stay up all through the night to suffer significant effects of sleep deprivation. Researchers from the University of New South Wales in Sydney, Australia, published a study in 2000 that compared the effects on performance of sleep deprivation and alcohol intake. They found that after 17-19 hours without sleep, participants performed as poor or worse than those participants with a blood alcohol concentration of 0.05%.

It’s not hard to imagine the risk a shift worker takes driving home after working 12 or more hours, especially if they haven’t gotten eight hours of sleep each night between shifts. Or consider the compounding effects of waking up for work at 7 a.m., getting off work to have a drink, and staying up until midnight before driving home.

The science is clear that sleep is critical to our ability to function, but it is still easy to be tempted to take the hit to performance and trade sleeping hours to get more done during our waking hours. To curb this temptation, zooming back out to the question of why we sleep can provide some important perspective.

SPRC faculty members Frank Marcos and Jonathan Wisor, alongside WSU professors James M. Kruger and Sandip Roy, published “Sleep Function: Toward Elucidating an Enigma.” It mainly discusses how a multitude of different frameworks offer varied explanations of sleep’s primary function, but in the process it outlines some of the fundamental and hugely important benefits that sleep provides.

One proposed sleep function is its role in our immunity. The study states, “There is substantial evidence indicating that sleep or sleep loss affects immune system parameters. For example, sleep loss is associated with a reduction in subsequent immunization-induced antibody titers.” An antibody titer is a test that measures the amount of antibodies in a person’s blood.

Another theory revolves around sleep’s glymphatic function. The glymphatic system is a recently discovered system that clears waste from the central nervous system.

The study states that, “Sleep-dependent enhancement of the removal of extracellular amyloid-β from the brain suggests that the sleep-wake cycle plays a role in the pathogenesis of Alzheimer’s disease.”

Amyloid beta peptide is a main component of the amyloid plaques found in the brains of individuals with Alzheimer’s disease. The article cites a study that found higher amounts of fluid volume in the brain during sleep or anesthesia as compared to a wakeful state, which reinforces the idea that the body is in a way “flushing” neurotoxic products out of the brain while we sleep.

Another explanation of sleep function revolves around neuroplasticity, the brain’s ability to form and reorganize neural connections, in particular in response to experiences where something new is learned. Plasticity is what helps us be so adaptable.

As stated in the study, “There is a broad spectrum of experimental evidence showing the effects of sleep and sleep loss on a variety of specific brain plasticity/connectivity mechanisms.” This includes mechanisms involved in cementing new memories and erasing obsolete ones, proactive cellular maintenance, and the overall stabilization, regulation and preservation of plasticity. In other words, all very critical functions for your ability to learn new things, remember things, recover from brain injuries, and maintain mental fitness.

The next time someone gives you grief for being a stickler and going to bed an hour early on the eve of daylight savings, just know that science has your back. It’s tempting to sacrifice those eight hours for an additional hour of fun or productivity, but it might not be worth it in the end. In our modern world obsessed with the balancing act between wellness and performance, sleep just may be your greatest ally.