Could Humans Hibernate?

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istock.com/ByronOrtizA

Some animals have it made. Their whole day revolves around eating and having sex (and, to be fair, trying not to get eaten themselves). And when winter arrives, they get to curl up somewhere and wait things out until the weather is nice again. Can humans get in on this hibernation thing?

First, a note on the lingo. While people often use the term loosely to refer to any state of dormancy in animals, true hibernation is a pretty specific thing characterized by “profound reductions in metabolism, oxygen consumption and heart rate.”

A hibernating animal’s core body temperature drops to extreme lows, sometimes matching the local outside temperature. As its body cools, its metabolism slows. This reduces the need for oxygen, and its breathing will also slow, sometimes to just one to five breaths per minute. The heart rate will likewise slow to just a few beats per minute. All of this ensures that the animal’s body will conserve as much energy as possible, which is necessary because it’s largely fueling itself with a limited supply of fat. "True hibernators" don’t shut down for the whole winter, though, and occasionally rouse to use the bathroom, eat from stored food, and stretch a little so their muscles don’t atrophy. Some animals may even switch hibernation spots.

Animals go into this energy-saving mode to ride out long stretches of environmental extremes, like lack of food and water, or very cold or very hot seasonal temperatures (dormancy during cold seasons is hibernation, and dormancy in the summer is called aestivation). Humans can deal with these situations while remaining active because we have things like canned food, greenhouse tomatoes, air conditioners, heaters, and turtleneck sweaters. Our bodies aren’t required to hibernate and we’re not perfectly adapted to it, but scientists have turned up a number of ways in which we’re pretty close.

Deep Sleepers

There are plenty of documented cases of humans going into hibernation-like states. In October, 2006, rescuers found Mitsutaka Uchikoshi 24 days after he’d gone missing on western Japan’s Mount Rokko. When they discovered him, he had no detectable pulse or respiration and his body temperature had dropped to 71 degrees Fahrenheit. Doctors would later confirm that his metabolism was almost at a standstill. When he woke up, remarkably showing no signs of brain damage or other ill effects, he explained that the last thing he remembered was falling on the trail and hitting his head. The entire time he’d been missing, he was unconscious, exposed to the elements and without food or water. The doctors who treated him said that the quick onset of hypothermia slowed his body down like hibernation would, and probably saved his life.

Similar survival stories include a Norwegian skier who’d fallen into icy water and woke up unfazed after showing no heartbeat, no respiration, and a core temperature of 57ºF, and the Canadian toddler who got lost outside on a cold night and was later revived after cooling to 61ºF and exhibiting no heartbeat for a full two hours.

In a controlled experiment in the early 1970s, the Yogi Satyamurti confined himself to a small, sealed underground pit in a state of deep meditation for eight straight days while being monitored by an electrocardiogram. At first, the yogi’s heart rate was normal, and then increased to 250 bpm for a while. On the evening to the second day, the ECG flatlined and remained like that until about 30 minutes before the pit was scheduled to be opened on the last day. The astonished researchers who’d been monitoring the yogi - whose core temperature had dropped four degrees in the pit - were sure that something was wrong with their equipment, but couldn’t find any malfunction or explanation besides the yogi’s heart stopping or decreasing in electrical activity below a recordable level.

It looks like our bodies have some of the abilities needed for hibernation. But like we said already, we’ve never had to, so our bodies aren’t completely adapted to the task. A few of the things holding us back are rather big obstacles. For example, researchers at the Paul Flechsig Institute for Brain Research in Leipzig discovered a few years ago that the brains of hibernating ground squirrels have brain cells containing modified proteins that are similar to those in the brains of Alzheimer's patients. The synapses that connect the brain’s neurons in both groups were also similarly degraded. The catch is that the squirrels’ brains bounce back after hibernation. They repair themselves and the animals show no signs of damage when they wake up in the spring, while human brains in the same state continue to deteriorate.

But hibernation on-demand would be useful to humans for reasons other than avoiding winter. Inducing hibernation in an accident victim on the way to the hospital could stave off extreme blood loss and cell breakdown, plus buy surgeons extra time to repair the injuries. It would also allow for the sort of space exploration that only seems possible in the movies. Placing astronauts in a dormant state, like in the Alien franchise, would allow them to sleep off the multiple years it would take for a spacecraft to travel to the outer reaches of the solar system and beyond.

Put to Bed

Researchers have been toying around with various ways to turn hibernation states “on” in animals over the last few years. Hydrogen sulfide seems to be one possible way to do that. By binding at the same cell sites as oxygen, the gaseous compound reduces the need for oxygen and depresses the metabolism. Mark Roth at the Fred Hutchinson Cancer Research Center in Seattle induced hibernation for the first time in lab mice in 2005 by having them inhale large doses of a hydrogen sulfide gas. Their metabolic processes slowed, their temperatures dropped, and then they snapped right out of it when they got a big breath of oxygen hours later.

Surgeons at Massachusetts General Hospital took a different approach in an experiment on Yorkshire pigs, to see how beneficial induced hibernation was in a trauma setting. After anesthetizing the pigs and giving them serious wounds that led to shock and extreme blood loss, the surgeons quickly chilled the pigs' bodies to 50ºF and pumped their veins full of a solution used for preserving transplant organs. At that point, the pigs were almost dead. They had little to no heartbeat, extremely reduced blood flow and no measurable electrical activity in the brain. The surgeons operated on the pigs and repaired their injuries. The pigs were revived when their temperatures were returned to normal and warm blood was pumped back in. The pigs bounced back with no noticeable physical or cognitive impairments.

While these are incredible breakthroughs and promising starts, we’re still a long way from making human hibernation simple, safe, and reliable. Other experiments failed to induce hibernation in sheep and pigs with hydrogen sulfide, so it might not work on larger animals, including us. Testing the Massachusetts method on humans, meanwhile, would be a bit tricky, ethically speaking. It’s a start, though, and sooner or later we might move beyond mere sleep and hibernate our way through surgery, or a flight to Jupiter.

6 Protective Mask Bundles You Can Get On Sale

pinkomelet/iStock via Getty Images Plus
pinkomelet/iStock via Getty Images Plus

Daily life has changed immeasurably since the onset of COVID-19, and one of the ways people have had to adjust is by wearing protective masks out in public places, including in parks and supermarkets. These are an essential part of fighting the spread of the virus, and there are plenty of options for you depending on what you need, whether your situation calls for disposable masks to run quick errands or the more long-lasting KN95 model if you're going to work. Check out some options you can pick up on sale right now.

1. Cotton Face Masks; $20 for 4

Protective Masks with Patterns.
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This four-pack of washable cotton face masks comes in tie-dye, kids patterns, and even a series of mustache patterns, so you can do your part to mask germs without also covering your personality.

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2. CE- and FDA-Approved KN95 Mask; $50 for 10

A woman putting on a protective mask.
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You’ve likely heard about the N95 face mask and its important role in keeping frontline workers safe. Now, you can get a similar model for yourself. The KN95 has a dual particle layer, which can protect you from 99 percent of particles in the air and those around you from 70 percent of the particles you exhale. Nose clips and ear straps provide security and comfort, giving you some much-needed peace of mind.

Buy it: $50 for 10 (50 percent off)

3. Three-Ply Masks; $13 for 10

Woman wearing a three-ply protective mask.
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These three-ply, non-medical, non-woven face masks provide a moisture-proof layer against your face with strong filtering to keep you and everyone around you safe. The middle layer filters non-oily particles in the air and the outer layer works to block visible objects, like droplets.

Buy it: $13 for 10 (50 percent off)

4. Disposable masks; $44 for 50

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Odash, Inc.

If the thought of reusing the same mask from one outing to the next makes you feel uneasy, there’s a disposable option that doesn’t compromise quality; in fact, it uses the same three-layered and non-woven protection as other masks to keep you safe from airborne particles. Each mask in this pack of 50 can be worn safely for up to 10 hours. Once you're done, safely dispose of it and start your next outing with a new one.

Buy it: $44 for 50 (41 percent off)

5. Polyester Masks; $22 for 5

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These masks are a blend of 95 percent polyester and 5 percent spandex, and they work to block particles from spreading in the air. And because they're easily compressed, they can travel with you in your bag or pocket, whether you're going to work or out to the store.

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6. Mask Protector Cases; $15 for 3

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You're going to need to have a stash of masks on hand for the foreseeable future, so it's a good idea to protect the ones you’ve got. This face mask protector case is waterproof and dust-proof to preserve your mask as long as possible.

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What Do Pets See When They Watch Television?

This dog would like to turn off Netflix's autoplay feature.
This dog would like to turn off Netflix's autoplay feature.
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In 2012, a television commercial aired in the UK for Bakers dog food that was conceived and produced specifically to attract the attention of dogs. The spot used high-frequency sounds that are inaudible to human ears. In theory, the dog would be so captivated by the advertisement that owners would take note and perhaps purchase Bakers for their next meal.

This didn’t quite work. Many dogs failed to react at all, proving that when it comes to television ads, humans may be more impressionable than canines.

While pets may not be so easily manipulated, they still find the television screen interesting, sometimes reacting to other dogs, animals, sounds, or images. But what is a dog really seeing when they tune in?

When it comes to color, television is no different from reality for a dog. They have dichromatic vision, which means they see the world through the range of two primary colors, yellow and blue. (Humans have trichromatic vision, able to see the full color spectrum.) Cone cells in canine eyes are also believed to blur their sight to a degree. More importantly, dogs process the frame rate, or “flicker fusion frequency,” of screens differently than people. Humans can detect movement at between 16 and 20 frames per second. Dogs need 70 frames per second or more. If they’re looking at an older television, it might resemble a flip book or even a strobe light effect to them. (Modern sets have a faster frame rate, which is why dogs might be more interested in your high-definition television.)

That helps explain the visuals. What about the content? Typically, dogs will react to the same things that would draw their attention in a room—barking, squeaking toys, or commands. In a study published in Animal Cognition in 2013, nine dogs were observed to see if they could pick out the face of another dog—regardless of breed—on a computer screen instead of another animal or a person. The dogs were rewarded with treats with a successful choice. Though the sample size was small, it indicated dogs can recognize other dogs on a screen. (Which you likely already knew if you’ve ever observed your dog suddenly on alert when a canine appears on camera.)

If your dog used to get excited by another dog on television but has since lost interest, it’s possible they simply became desensitized to their appearance, realizing the image in front of them isn’t going to move out of the boundaries of the monitor.

Content unrelated to dogs might not be of much interest. In a 2017 study published in the International Journal of Human-Computer Studies, dogs presented with three different viewing screens didn’t exhibit any particular preference for one over the other. If they were shown three screens at one time, they seemed uninterested in watching anything at all.

The study also noted that dogs had a limited television attention span. Rather than mimic the binge-watching habits of humans, dogs prefer to glance at a screen for a few seconds at a time. But that behavior could also be breed-specific. Dogs bred for hunting might be interested in moving objects, while dogs that rely more on smell might be indifferent.

And what about cats? In a study published in Applied Animal Behaviour Science in 2008, 125 shelter cats were given a television to view for up to three hours a day. The cats were split into five groups and given a variety of programming to watch, from humans to footage of prey to a blank screen. On average, cats spent just 6.1 percent of the observation time watching the screen. When they did, it was mostly to focus on the prey.

Because cats may react to images of birds and rodents on television, owners should avoid letting them watch unattended. You can also secure the set to a wall to make sure they don’t knock it down.

For the most part, dogs and cats are far more interested in what’s going on in the real world compared to what's on TV. We could probably take a lesson from their limited screen time.