Is human hibernation the key to a manned mission to Mars? Newly discovered fossils suggest that early humans may have “slept through” the winter

It’s that – dark, cold – time of year when memes fly around in hibernation on social media. “Wake me up in the spring!” be a classic example.

It is normal for people to sleep a little longer in winter. Reduced exposure to light tells the body to produce melatonin, a hormone that makes us sleepier. But what if people could actually hibernate?

Some scientists believe it could be closer than we think, with a range of potential benefits from preventing damage from cardiac arrest and stroke to staving off starvation – and even enabling space travel.

Dr. Marina Blanco, a researcher at Duke University in the US who has studied hibernation in pygmy lemurs, told Good Health: “Inducing hibernation in humans may be more science than fiction.

“It can help us survive ‘energy crises’ – for example, seasonal food shortages – and deal with serious injuries by preventing organ damage and extending lifespan.”

The problem with injuries is that the sudden restoration of blood flow to a tissue whose supply is blocked, such as after a heart attack or stroke, can lead to fatal trauma.

However, research on mice has shown that “that trauma is significantly reduced” if you keep them cold when the blood supply returns, explains Dr Hibernation Research. in animals.

One of the main reasons for this is that the common cold “reduces metabolic activity in the mitochondria, which are essentially the powerhouses in the cell,” he says.

“When the blood returns, the mitochondria are quickly reactivated, and this creates byproducts that can be harmful. By slowing the rate at which they switch back on after blood flow returns, hypothermia protects vital organs from this burst of activity.”

Hibernation is a state of minimal activity and metabolic slowing experienced by some animals – hedgehogs, bats and brown bears are well known – characterized by reduced heart rate, body temperature and reduced oxygen consumption. This allows these animals to survive periods of cold and starvation, which can last for days, weeks or even months, depending on the species.

Other animals experience a similar but shorter state called torpor, in which body temperature, respiratory rate, heart rate and metabolic rate decrease.

But unlike hibernation, dormancy appears to be an involuntary state that an animal enters when it needs to conserve energy, such as when food is scarce. Many birds and small rodents, such as mice and hamsters, fall asleep frequently.

However, not only animals do this. Bone evidence from one of the world’s most important fossil sites, a cave called Sima de los Huesos (‘bone pit’) at Atapuerca in northern Spain, now suggests that hundreds of thousands of years ago, early humans may have survived the extreme cold by sleeping in the winter.

One suggestion is that it could reduce astronauts’ food needs during a long, years-long space journey – such as the 300-million-mile trip to Mars

The fossils in the cave show seasonal variations that suggest bone growth was disrupted for several months of the year, according to a paper published in the journal L’Anthropologies.

The researchers argue that these early humans “were in metabolic states that helped them survive for long periods in cold conditions with limited food stores and adequate stores of body fat.” In other words, they hibernate.

And while humans no longer sleep or hibernate, growing evidence suggests that we may carry the biological hardware to do so.

Dr Blanco explains: “Humans, like other mammals, may already have the biological ‘machinery’ for hibernation, but we need to figure out how to activate, regulate and coordinate all the necessary processes.”

This “machinery” is essentially the information stored in our genes.

DR Ambler agrees, “If you look at a hibernating bear, it doesn’t have hibernation genes that humans don’t. It has modulating genes common to all mammals.

“This appears to be a common and ancient behavior, and there are primates that continue to do it to this day.” In fact, Dr. Decades after they lost the habit of living in captivity, Blanco induced hibernation in pygmy lemurs by carefully regulating the temperature of their enclosure—proof that the ability to hibernate can be reactivated.

Pygmy lemurs, native to Madagascar, are warm-blooded primates like us, but during hibernation they can lower their body temperature and slow their metabolism until their bodies need only 2 percent of the energy they normally need.

Meanwhile, the experiments of Dr. Ambler induced anesthesia in rats – which normally don’t get into that state – by using genetically engineered viruses to turn on the area of ​​the brain responsible for anesthesia in mice, further suggesting that it might be possible to using other mammals. He argues that the potential human impact is enormous.

“Scientists are increasingly considering whether we can use components of hibernation for clinical utility,” he says.

Dr. Ambler adds, “There is a paradox in critical care medicine. People get very sick and their organs begin to fail, so we try to save them from death by normalizing their physiological functions, such as: B. the amount of oxygen the lungs can absorb .

“But the interventions themselves, such as ventilators, cause damage. If we can reduce a person’s oxygen needs by making them hibernate, this damage can be prevented.”

However, the technique needs to be refined, because although “therapeutic hypothermia” has been widely used in hospital intensive care units since 2002, where the body is cooled after a traumatic injury or cardiac arrest, it is no longer commonly used today. It is thought to slow metabolic processes such as the breakdown of glucose in cells, reduce the amount of oxygen the brain needs to function, and slow brain cell death. However, this carries significant risks.

These include a reduced ability of blood to clot, which can potentially cause bleeding, increase blood sugar levels and cause an abnormal heart rhythm.

Recent studies have shown no benefit, although this is still being done in premature babies with postpartum brain damage.

But could the reduced metabolism of torpor, or hibernation, have uses other than medical treatment?

One suggestion is that it could reduce astronauts’ food needs during a long, years-long space journey — such as the 300-million-mile trip to Mars.

Both the European Space Agency (ESA) and NASA are seriously interested in this area of ​​research, and earlier this year an ESA-led study suggested that human hibernation could become a breakthrough space technology.

And during space travel, astronauts are exposed to radiation — hibernation can help reduce that risk.

Dr. Ambler explains: “Exposing a hibernating animal to radiation appears to protect it from harm.

“It turns out that when your cells aren’t very active, the DNA is coiled up more tightly, making it less likely to disintegrate and break down.”

However, there is still a lot to sort out before we can all curl up for an extremely long nap.

All hibernating mammals wake up frequently during hibernation, which means their heart rate increases and body temperature rises. How often this happens depends on the species.

It is believed that this is done to allow the animals to breathe more deeply and warm up their bodies. You can even eat.

Dr. Blanco says, “We tend to think that the hardest part of getting people to hibernate is maintaining a suppressed metabolism over the long term.

“In fact, perhaps the biggest challenge is the physiological stress associated with arousal, the drastic metabolic jumps that naturally occur every few weeks during a hibernation period.”

“How can we make a heart beat from six times a minute to more than 200 times without suffering physical damage?”

Despite these risks, the potential benefits are compelling.

as Dr. Soos Ambler puts it, “The capacity to care for critically ill patients can be greatly increased.”