podcast
Chasing Life
All over the world, there are people who are living extraordinary lives, full of happiness and health – and with hardly any heart disease, cancer or diabetes. Dr. Sanjay Gupta has been on a decades-long mission to understand how they do it, and how we can all learn from them. Scientists now believe we can even reverse the symptoms of Alzheimer’s dementia, and in fact grow sharper and more resilient as we age. Sanjay is a dad – of three teenage daughters, he is a doctor - who operates on the brain, and he is a reporter with more than two decades of experience - who travels the earth to uncover and bring you the secrets of the happiest and healthiest people on the planet – so that you too, can Chase Life.
How Hibernation Could Redefine Space Travel and Medicine
Chasing Life
Feb 20, 2026
Animals can hibernate, slowing down most metabolic functions — heart rate, blood flow, brain activity, and body temperature — then waking as if nothing happened. Humans have never done this, but what if they could? Could hibernation extend life or even save it? Dr. Sanjay Gupta explores global research into the molecular mechanics of hibernation and how these abilities might one day help fight cancer, prevent heart disease, treat depression, and even enable travel to Mars.
This episode was produced by Amanda Sealy
Medical writer: Andrea Kane
Showrunner: Amanda Sealy
Senior Producer: Dan Bloom
Technical Director: Dan Dzula
Episode Transcript
Dr. Sanjay Gupta
00:00:02
Welcome to Chasing Life. Hibernation. We've all heard the term and might even think we know what it means. Bears and squirrels, other animals hunkering down for the winter, only to emerge when the warmer weather of spring arrives. But what if hibernation itself was more complicated than we realized?
Ryan Sprenger
00:00:23
His heart rate will go from about three beats a minute to upwards of 400 beats per minute in about 10 minutes.
Dr. Sanjay Gupta
00:00:30
Wow. That's incredible.
Dr. Sanjay Gupta
00:00:31
And what if hibernators had superpowers that could one day be tapped for humans, for things like cancer, heart attacks, depression, and even space travel? Those are the questions researchers and scientists all over the world are getting closer to answering every day. I'm Dr. Sanjay Gupta, and this is Chasing Life.
Dr. Sanjay Gupta
00:00:58
Christopher Gregg is a professor of neurobiology and human genomics at the University of Utah. But his work on human genes has led him to a completely different type of mammal, hibernators.
Dr. Christopher Gregg
00:01:12
We were trying to crack the code on the genome to find these switches that control our genes. Our idea was that we could compare the genomes of species with a particular trait against species that didn't have that trait. And we were excited about traits that were to do with behavior, metabolic control. And as we went through all of the superpowers that have evolved, hibernation just jumped out at us.
Dr. Sanjay Gupta
00:01:42
Hibernation, in its simplest form, is not sleep. Instead, it's a length of time when an animal's metabolic activity drops dramatically. That state of lowered metabolic activity is called torpor, and most hibernators cycle in and out of that throughout hibernation. When that happens, body temperature can drop to the point of freezing. Heartbeat, respiration, and blood flow all slow, parts of the brain shut down, and the aging process itself grinds to a halt. In essence, it's a full body shutdown to conserve energy. In 2016, researchers in Gregg's lab were able to isolate and compare specific parts of the genome of hibernators to the human genome. And in doing so, they made a discovery.
Dr. Christopher Gregg
00:02:32
Hibernators are changing how these genes behave, and we found the specific regulatory elements that we think are important for doing.
Dr. Sanjay Gupta
00:02:43
Now, think of the human genome as a house. In the house, there are light switches with corresponding lights. Your genes are those light switches. They contain instructions on how to build, maintain, and run your body. We share many of these light switches, or genes, with most hibernators. The key difference is that hibernaters have developed ways to turn those shared light switches on and off.
Dr. Christopher Gregg
00:03:09
This is a very cool data set. I see what you mean by the strength of the signal.
Dr. Sanjay Gupta
00:03:14
Armed with this knowledge, the lab's research is now being applied in the fight against cancer.
Dr. Christopher Gregg
00:03:20
Most people think of hibernators, they think of the gaining of all the body fat and then the losing. Lesser known is that when hibernators have cancer, the cancer stops growing when they're in torpor. It stops spreading, what they call metastasizing.
Dr. Alana Welm
00:03:42
Have we been?
Dr. Christopher Gregg
00:03:43
Uh, mostly pretty good.
Dr. Sanjay Gupta
00:03:45
This time, his work is personal.
Dr. Alana Welm
00:03:48
Show you the tumor markers. Yeah, so this is the first time they've consistently both gone down.
Dr. Christopher Gregg
00:03:57
I have a rare form of cancer, a male breast cancer. I was diagnosed in 2018 with stage four disease, so it's advanced. That's unfortunately a terminal diagnosis.
Dr. Sanjay Gupta
00:04:12
'Since early 2025, he's been working alongside researchers Alana Welm and K-T Varley. They're at the Huntsman Cancer Institute in Utah. And their goal is to figure out why cancer cells go dormant, how they stay dormant and then what reactivates them.
Dr. Alana Welm
00:04:29
We have known for decades that cancer cells can be in the body in an undetectable state from old autopsy studies.
Dr. Sanjay Gupta
00:04:38
'Starting in 2022, the multi-year research program called the TRANCE Project launched a rapid autopsy program to study these invisible dormant cancer cells known as Disseminated Tumor Cells, or DTCs.
Dr. Alana Welm
00:04:52
But we didn't know the relevance necessarily of those cells that we can detect and study to the ones that arise in your other organs that can lead to death. But eventually we actually had a patient here who was keen on donating her tissue when she died of breast cancer. So we made it happen. Since then we realized, look, this is an important enough issue that we really can do it with cooperation with patients and really, you know, dive into what is their DNA doing?
Dr. Sanjay Gupta
00:05:26
This is where the hibernation data comes in.
Dr. Christopher Gregg
00:05:29
Given that we had identified parts of the genome that seemed to be in human cells and linked to the evolution of hibernation, can we intersect those data sets with the data sets that we've developed around hibernations to identify what we think are the key genes and switches that are involved in that dormancy state?
Dr. Sanjay Gupta
00:05:52
To date, seventeen patients have shared their cells from both active tumors as well as other distant organs. Each sample is a snapshot of living tissue for researchers to study.
'Dr. K-T Varley
00:06:02
Some of the first things we've seen is that there's differences in the genes that are turned on when a breast cell is trying to live by itself in the liver versus in the lung. I think that's gonna give us a great handle on what their vulnerabilities are, right? How can we kill them when they're in those vulnerable states by learning how they're surviving now?
Dr. Sanjay Gupta
00:06:24
While the research comparing the datasets is still in its nascent stage, Gregg remains determined and hopeful.
Dr. Christopher Gregg
00:06:31
I can't work on things that will take 20 or 30 years to solve. I fundamentally believe in this idea, and so I think it can be achieved in a reasonable period of time.
Dr. Sanjay Gupta
00:06:41
So what if that same metabolism they're looking to target in cancer cells could also change the game for other health issues, like heart disease? And what if the solution lies in squirrels?
Dr. Sanjay Gupta
00:06:57
Is there a champion hibernator when it comes to animals?
Dr. Ashley Zehnder
00:07:00
'Yeah, I mean thirteen-lined ground squirrels are really good. We call them the Usain Bolts of hibernators because they're excellent at it.
Dr. Sanjay Gupta
00:07:07
It's a tiny creature that weighs no more than nine ounces at most. Native to Central North America, found as far north as Alberta, Canada, and as far south as the Texas coastline, these squirrels undergo remarkable changes during hibernation.
Dr. Ashley Zehnder
00:07:23
They go through what's almost like a mini heart attack or stroke every couple of weeks, so 25 times over hibernation period.
Dr. Sanjay Gupta
00:07:29
'That's Ashley Zender, CEO and co-founder of Fauna Bio.
Dr. Ashley Zehnder
00:07:34
The neurons in their brain physically retract during hibernation. So they have a flat EEG, the retinal, the cone photoreceptors in their eye, which see vision, physically melt and reform every couple of weeks. So this is an animal that's evolved over hundreds and millions of years to repair damage that happens during this really dramatic hibernating course using the same genes that you and I have, but in slightly different ways.
Dr. Sanjay Gupta
00:07:58
Today I'm seeing them up close in Oshkosh, Wisconsin, at the university here. I've got to tell you, I didn't quite know what to expect. I was told I was going to a lab, so I imagined a brightly lit space with lots of test tubes and beakers, but instead I'm in a dark room known as a hibernaculum. It's lined with shelves of boxes of hibernating animals just stacked one on top of the other. The squirrels here are part of a bred colony being studied by researchers from a biotech company called Fauna Bio. This hibernaculum, as it is called, is set to just four and a half degrees Celsius, not that far off from the body temperatures of the hibernating squirrels themselves.
Katie Grabek
00:08:42
'So they'll spend about one to three weeks in continuous torpor. They'll periodically re-arouse back to normal body temperature. That'll last about 12 hours, and then they'll go back down in the torpor, and then this lasts for months.
Dr. Sanjay Gupta
00:08:57
'Katie Grabeck is the chief scientific officer and co-founder for Fauna Bio.
Katie Grabek
00:09:01
They lose most of their fat, but they still preserve all of their lean mass, which is quite amazing. They don't lose their muscle, so when they come out they're ready to run around and mate.
Dr. Sanjay Gupta
00:09:13
There seems like some real lessons in that, in the fact that they maintain that muscle mass despite the fact they go for months without movement, without eating really anything.
Katie Grabek
00:09:25
Yes, and that's one of the things we're interested in, is how, you know, for us, if we rested in bed just even for a few days, we're going to start losing muscle mass and then pair that with not eating at all, fasting, and you're going lose a lot of muscle mass. These animals, not only do they preserve it, it looks like they put on a little bit of muscle before they come out of hibernation.
Dr. Sanjay Gupta
00:09:47
That's amazing. Can we see one of these animals? Can we get a better look?
Dr. Sanjay Gupta
00:09:52
Now these squirrels are what are called obligate hibernators, which means stimuli like warmth and light will not be enough to keep them from going into torpor. In other words, they are hardwired to hibernate.
Katie Grabek
00:10:06
Hibernating ground squirrel, disease in torpor. Still has reflexes going.
Dr. Sanjay Gupta
00:10:12
So these are just kind of brain stem reflexes, is that the movement that we're seeing?
Katie Grabek
00:10:16
Yes.
Dr. Sanjay Gupta
00:10:17
Let me just take a second to describe what I'm seeing. Katie just took one of the squirrels out of its box, and now it's in a brightly lit lab. It's kind of unfurling and moving its limbs, almost like it's stretching.
Katie Grabek
00:10:31
So, most of the brain is shut down right now. And if you did an EEG on brain waves, you wouldn't find much, but two regions of the brane remain active, the hypothalamus and then the brain stem. So that keeps the heart rate going and breathing everything that's needed for the animal to still be alive and function.
Dr. Sanjay Gupta
00:10:50
And again, all the movement that we're seeing here is just mostly brain stem reflex.
Katie Grabek
00:10:56
In the hypothalamus, there's certain populations of neurons in the hypothalmas that are really controlling that suppression of metabolic rate. So the animal goes into torpor. So it's also keeping the animal there in torpor.
Dr. Sanjay Gupta
00:11:11
'To go from the deepest state of torpor to fully awake, Grabek says the squirrel's metabolic activity will spike to around 235-fold from the torpor baseline. That extraordinary jolt is what drives its body temperature from four degrees Celsius to 37 degrees Celsius and gets blood flowing again. In all, the process takes just under two hours, and a key part of this transition involves the heart.
Dr. Sanjay Gupta
00:11:39
So we're about to see something that's very rarely been done. Actually I'm doing an echocardiogram, actually looking at the heart of a squirrel in torpor.
Ryan Sprenger
00:11:50
'There's a great short-axis view. So did you see the interior of the left ventricle contracting?
Dr. Sanjay Gupta
00:11:54
Oh yeah, I see it. Okay, right. We're talking about right here.
Ryan Sprenger
00:11:57
Exactly, yep, right there. So that's the interior of the left ventricle. So now he's starting to speed up. So this is a really great example of this animal's still very cold. Metabolic rate's still coming up, but his heart is still starting to increase in rate.
Dr. Sanjay Gupta
00:12:12
Within a span of 12 minutes, the squirrel's heart rate went from around 3 beats a minute to more than 107 a minute, eventually reaching the normal range of between 300 to 400 beats per minute.
Katie Grabek
00:12:24
You see the heart rate really rapidly increase and it's still not getting enough blood flow to the heart itself, enough oxygen, but it has to work to get the animal to warm up.
Dr. Sanjay Gupta
00:12:36
When the heart is not getting enough blood flow, that's what can cause a heart attack. But that is not happening here. Like, if you measure things, did this squirrel have a heart attacks?
Katie Grabek
00:12:48
'So when researchers have looked at the histology of the heart, there are markers of damage that look like it had a heart attack that somehow get repaired for us will lead to long-term heart damage and fibrosis. Somehow it can repair it before it goes back down, back into torpor. It looks like they're re-expressing the cardiac fetal genes, so involved in stem cell renewal and repair. So we think that some of these squirrels are a little bit more regenerative than what was previously thought. And it kind of makes sense that if they know they're going to damage their heart to get out of torpor and they have to do this 25 times over the winter, they have to figure out how to fix it or else they're not going to live very long, right? Whereas for us, that never really happens to us in the course of our lifespans. We're not going to take on damage we know about. So evolutionarily, again, there's pressure to fix things when you damage them.
Dr. Sanjay Gupta
00:13:49
The squirrel's genetic ability to jumpstart its heart so quickly and safely without lasting damage is exactly what Fauna Bio is hoping to mimic.
Dr. Ashley Zehnder
00:13:58
What we're looking at are really two different aspects of cardiac disease. Initially, what we were looking at is really protection from what's called acute myocardial infarctions. Can we protect the heart from damage from that acute injury? But as we started to look particularly at the genomics of our lead program, what we saw is that there were humans with a certain type of heart failure called HFpEF, the kind of heart failure that affects about half of all heart failure cases around the world. It's really characterized by a stiffness in the heart that doesn't allow blood flow normally. So how do we have a heart be able to relax and beat better?
Dr. Sanjay Gupta
00:14:29
'The company has used their AI platform to compare data from genetic biobanks of both hibernators and humans around the world. This tech sifts through a combination of compounds and genes looking for one that could turn on the gene to protect human heart cells. They've since entered into pre-clinical safety trials for a drug that they have identified, developed, and then validated on human cardiac cells in the lab.
Dr. Ashley Zehnder
00:14:55
And so our goal is to really be able to develop new therapeutic approaches for many different diseases and help, at the end of the day, humans live longer and healthier lives, not through hibernation, but through learning insights for how these animals survive this really punishing hibernating cycle.
Dr. Sanjay Gupta
00:15:12
Up next, could these squirrels be the key to getting humans to Mars?
Dr. Sanjay Gupta
00:15:24
The brain, it's the command center for every breath we take, heartbeat, step, and even hibernation. Nature has already shown us what is possible. Now this man, Dr. Genshiro Sunagawa, wants to imagine a future where we humans can do it too.
Dr. Genshiro Sunagawa
00:15:43
Our mission is to make humans hibernate, so we are trying to develop a technology which can make humans hibernate safely and efficiently.
Dr. Sanjay Gupta
00:15:55
Here at the RIKEN Laboratory for Hibernation Research in Kobe, Japan, scientists are studying hibernation using genetically modified mice. In 2020, Dr. Sunagawa was part of a research team that discovered that by triggering specific neurons in the brains of these mice, they could induce torpor. Now here's the thing, mice do not naturally hibernate, and neither do humans. And that means this finding could lead us one step closer to a world where scientists can "flip the switch" on human hibernation. And for us, that could mean a lot.
Dr. Genshiro Sunagawa
00:16:30
So you can see this, yeah, this guy with the hair is me.
Dr. Sanjay Gupta
00:16:35
You know, Dr. Sunagawa was a pediatrician first, and it was actually his young patients who first inspired his passion in hibernation biology.
Dr. Genshiro Sunagawa
00:16:43
I was working in an ICU or ER where there are so many severely ill kids. But I also learned a lot that even in the current medicine, there are so many situations that we cannot even save their lives. And that was kind of striking for me.
Dr. Sanjay Gupta
00:17:08
The more he researched, the more he realized what other benefits inducing hibernation in humans might serve, including saving the lives of critically ill patients being transported to the hospital, during surgery...
Dr. Genshiro Sunagawa
00:17:21
Just imagine that if you don't need to breathe a lot during hibernation, if the surgery is very small, very short, maybe hibernation will be used instead of general anesthesia.
Dr. Sanjay Gupta
00:17:35
And in organ transplants, where timing is absolutely critical.
Dr. Genshiro Sunagawa
00:17:38
If we use hibernation at the cellular or tissue level, I think we can use them for preserving organs for the transplants.
Dr. Sanjay Gupta
00:17:50
Beyond emergency medicine, RIKEN's research here could also make an impact on the way we look at mental health. By studying the responses of stressed mice, Dr. Sunagawa is also in the early stages of research into the link between hibernation and seasonal affective disorder. That's a type of depression linked to the changing of the seasons, especially during winter. He believes the two could share the same origin or core purpose.
Dr. Genshiro Sunagawa
00:18:18
If these conditions share a mechanism, if we go further, if we do enough research about natural hibernation, we might find a new, novel way to deal with this depressive state. I believe that if we discover that this depression system is very similar to hibernations, we can tell those people that, okay, depression itself was a kind of function which human had in the past to survive, for example, the ice age or those period when we had much more severe winter. And it's not your fault.
Machine voice
00:19:07
"Hibernation activated."
Dr. Sanjay Gupta
00:19:09
'And with the science ever-evolving, we come back to the final frontier. The thing that everyone asked me about when I told them I was gonna be doing this was space travel.
Dr. Ashley Zehnder
00:19:19
Of course, yeah.
Dr. Sanjay Gupta
00:19:20
Would hibernation be relevant?
Dr. Ashley Zehnder
00:19:22
Yeah, there's been sort of this long intersection of space travel and hibernation. There's this kind of natural linkage between people who are trying to cool humans down to lower their metabolism to enable long term space travel. Whereas these animals reduce their metabolism and thus they get cooler. And so it's kind of this more natural but opposite way to get that metabolic cost savings. In addition to that, we've shown even on earth that animals when they're hibernating are protected, for example, from radiation. That's a big risk for humans as they spend longer time in space.
Dr. Sanjay Gupta
00:19:55
Back in Oshkosh, the race is on to study squirrels in space. Okay, so what are we looking at here?
Dr. Christopher Gregg
00:20:01
Yeah, so this is what we call the respires unit.
Dr. Sanjay Gupta
00:20:03
Ryan Sprenger is a senior research physiologist at Fauna Bio.
Ryan Sprenger
00:20:07
It's a unit that we developed as part of funding that we got from NIAC, NASA Innovative Advanced Concepts.
Dr. Sanjay Gupta
00:20:14
The respires unit he is showing me is basically a small metal cylinder.
Ryan Sprenger
00:20:18
'And the reason we're developing this unit is because we don't currently have the capability one to study hibernation in space and two to study physiology in space. So we have designed it to have two synchronously hibernating animals in space transferred to the ISS. And we have it set up so that we can provide air to the animal. We can provide infrared camera viewing. And this is also designed as something called a plethysmograph which allows us to measure metabolism and ventilation. And we also anticipate telomere-ing the animal so we can grab as much physiology as we can possibly grab to inform us on what their hibernation phenotype looks like.
Dr. Sanjay Gupta
00:20:52
The thing that you're trying to learn the most here is basically, is hibernation the same in space as it is on Earth?
Ryan Sprenger
00:20:59
Yeah, I would say that's primary question number one. Does hibernation happen in space and is it the same? Secondary question is, if they do commence hibernations in space, do we see the same protections that we anticipate to see on the ground?
Dr. Sanjay Gupta
00:21:13
'Beyond squirrels, researchers at the University of Pittsburgh, in Pennsylvania, recently concluded studies in conjunction with NASA that put humans in a torpor-like state for up to 20 hours at a time across a five-day period. They did so by using an FDA-approved sedative, dexmedetomidine. In this state, the blood pressure, heart rate, and temperature all dropped among study participants and their need for food and oxygen also decreased by 20%. And yet, they could still wake up quickly and even perform tasks like exercise and operating a computer. Now, they're looking to the next phase of the study to see what impacts these types of torpor-like states could have on the human body. There is so much to learn from these hibernating animals, the things they can teach us, how to prevent heart disease, how to build muscle, treat diabetes, even potentially make it easier for us to go to Mars. So the next time you see an animal burrowing into the ground in the cold winter, recognize there might be some real treatments for all of humanity. Thanks for listening.
