Not enough sleep throws your circadian rhythm off, leading to potential cognitive problems

Sleep deprivation leads to a shutdown in the production of essential proteins.

Not enough sleep throws your circadian rhythm off, leading to potential cognitive problems
Photo by Ulrich Baumgarten via Getty Images
  • Two new studies indicate what happens when your natural circadian rhythm is disrupted by not enough sleep.
  • The production of essential proteins is disrupted by a lack of sleep, which could result in cognitive decline.
  • From dementia to an uptick in obesity, sleep deprivation wreaks havoc in your physiology.

As sleep science continues to discover the necessary benefits of a good night's rest, roughly one-third of Americans sleep less than six hours every night. Two new studies, both published in the journal Science, and both conducted on mice, have deepened our understanding of why sleep matters so much to cognitive and physical health.

The downsides of sleep deprivation are well-known. From an increase in automobile accidents to stark cognitive decline (sometimes leading to dementia) to weight gain, a regular sleep schedule is the best recovery tool we have in our biological arsenal. Napping has been shown to help, though the eight-hour overnight prescription seems to hold up best, for most people. Sleeping too much, it turns out, has adverse affects as well, but that's not a problem most run into.

For the studies published in Science, researchers were able to better understand the relationship between sleep cycles and our circadian rhythm, the internal timekeeper that preps us for shutting down and waking back up. While a number of factors play into that rhythm — screen time, caffeine intake, habitual behaviors, work schedule — by honoring its natural cycle you prime for your body for optimal health.

Falling off the cycle, it turns out, disrupts communication between the neurons necessary for maintaining a healthy relationship to our nightly ritual.

The Science of Sleep

In the first study, researchers at the University of Zürich discovered that our circadian rhythm regulates protein transcription. When you're feeling tired and head off to bed, the proteins necessary for healthy cellular functioning are produced, peaking at two points in the day: right before bed and upon waking up. Sleep sets into motion the transcripts for protein-building, while waking up promotes synapse-firing, the communications device that allows neurons to speak.

When mice were deprived sleep, the transcripts malfunctioned. The messenger RNA (mRNA) were unable to deliver the messages necessary for completing the protein-building and synapse-firing phases that sleep provides. The team, led by Sara B. Noya at the Institute of Pharmacology and Toxicology, writes:

"Under conditions of high sleep pressure, one-fourth of mRNAs remained identically circadian, and most preserved some degree of circadian rhythmicity. In contrast, no substantial circadian rhythm could be detected in any protein when sleep pressure was constantly high."

The takeaway: honoring your circadian rhythm — some of us are early risers, others late to bed, so nuance matters; what appears stable is that seven-to-nine hours of sleep works for most everyone — will result in the proper building of proteins and communication between neurons. Depriving yourself of sleep will not only make you tired; your mental health will pay the price over time.

Illustration of the biological clock. Depending on sunlight perceived by the eye, signals are sent to the suprachiasmatic nucleus, home of the circadian clock, located in the hypothalamus, which controls various biological rhythms. The brain controls the secretion of melatonin (sleep hormone), which increases as light diminishes.

Image source: Jacopin / BSIP / Universal Images Group via Getty Images

For the second study, a team led by Franziska Brüning (Ludwig Maximilian University of Munich; the Max Planck Institute of Biochemistry) measured the attachments of a phosphate molecule that turns these proteins on and off every four hours, aka "circadian clock-driven protein phosphorylation." Previous studies have measured this process every 24 hours, making this new research more revealing in terms of how these proteins operate.

As with the companion study above, they discovered two peaks, one upon sleeping, the other before waking. The team writes that previously it was not well understood how time of day affected phosphorylation. By depriving mice of sleep, an abundance of the process was lost in forebrain synapses. They write:

"Our data uncover molecular processes in synapses whose activity is temporally gated by phosphorylation, such as synaptic inhibition at dawn and excitation at dusk."

Maria Robles, who took part in both papers, says these companion studies reveal the our brain has developed "a beautiful way to control" the molecules necessary for healthy physical and cognitive functioning. While mice are not men, our shared DNA allow such studies to reveal the inner workings of human physiology. These two studies bring us closer to revealing what we already instinctually know: nothing replaces a good night's sleep.

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A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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