Transcriber: Ananya Sandeep Reviewer: Emma G
[A thought for everyone], could humans hibernate?
Would you do it if you were offered the chance?
What is it like to hibernate? Is it like sleep without dreams?
Would you feel cold, depressed, helpless, even like you are dying?
Would you feel pain? Would you come back the same person
as you were before, after prolonged hibernation?
My name is Vladyslav Vyazovskiy I am a sleep neuroscientist
at the Department of Physiology,
Anatomy and Genetics at the University of Oxford.
And in the next 15 minutes or so,
I will talk about hibernation and whether it’s possible for humans.
Hibernation is a very odd state,
which is difficult to get your head around
if you think what it means physiologically, but also experientially.
Yet the fact that it exists makes so much sense.
It is, first of all about energy conservation
and is precisely why so many animals in the wild hibernate
and is why it is so widespread across the animal kingdom.
Energy is precious for life, because without it,
your brain and the body simply cannot function.
As you know, of course, just a few seconds without oxygen
results in unconsciousness
and in a few minutes may lead to death or irreversible changes.
So reducing metabolic demands would enable survival for much longer,
with only minimal provision of oxygen and nutrients.
We now know a great deal of how energy is produced in every cell in our body,
how the brain controls body temperature,
or how hormones and neuropeptides regulate metabolic status.
What we understand much less is how animals decide
when and how to enter this fascinating state of being.
I became interested in hibernation about 25 years ago,
and I did a master’s project
at the Kharkiv Institute for Problems of Cryo Biology and Crime Medicine
at the National Academy of Sciences of Ukraine.
Back then, I chose to work in the lab where scientists studied
the effects of cold temperatures on the brain,
seeking ways on how to treat neurological and neuropsychiatric disorders.
Later I did a PhD at the University of Zurich in Switzerland
in a laboratory where scientists studied Dzungarian hamsters.
This very peculiar species employing so-called daily torpor.
So daily torpor is described as a drop-off metabolism
lasting typically just a few hours,
and which we can detect this bouts of torpor
by measuring their body temperature.
So, remarkably, all you need is to shorten the day
to switch their physiology into this energy conservation mode,
so the animals think it is winter
and over the next few weeks, they turn white
and they start entering torpor almost every day.
Interestingly, scientists find that most animals enter torpor via sleep.
It seems you must fall asleep first,
as if sleep opening the gate into the state of hibernation.
However, hibernation or torpor is something very different from sleep.
It cannot be a substitute for sleep.
For example, it was noted that hibernating animals
such as ground squirrels, do not remain torpid throughout the winter,
but they rewarm regularly for about a day or so, every few weeks.
And interestingly, they spend a considerable proportion of time
during those arousals, sleeping.
Also, hamsters go to sleep every time when they emerge from a bout of torpor.
As if all these animals were tired of hibernating.
Now it's time to turn to the key question. So could humans hibernate?
Whether humans can hibernate is probably
the only big question that remains on strong footing
in the domains of science and science fiction at the same time.
So there is obviously enormous practical interest in human hibernation
from long distance space travel
to potential clinical applications here on Earth,
which are many and varied from cancer treatment, neurodegenerative disorders,
stroke, aging and even organ preservation.
I have to say that much confusion still remains
about what human hibernation might look look like at the end.
In science fiction movies,
you often see humans lying in pods completely immobile
and seemingly unconscious.
Such a state is often called suspended animation or cryosleep.
Cryo often implies low, even freezing temperatures.
So it sounds extreme, but there are animals, even vertebrates,
that can survive temperatures below zero
as they have developed elaborate physiological mechanisms
preventing the formation of ice crystals in their cells.
But do not worry, this is not what scientists would want to do to humans.
The idea is to simply reduce the metabolic rate.
Ideally without cooling down the body at all.
It is still unknown how it feels to hibernate and if you would have dreams.
The profound reduction of all physiological processes
during hibernation will naturally impact the brain
and will therefore have major effects
on how you process sensory information or your behaviour.
We know that the brain is highly active during sleep,
but in a somewhat different way from wakefulness.
But it’s remarkable how little we know
on what happens in the brain during hibernation.
This is one of the main research directions in my laboratory in Oxford.
I suspect that during hibernation,
what would be experienced is some sort of altered state of consciousness
when time ceases to exist or runs at a slower rate.
In a way, this is one of the key motivations
why we would want to develop hibernation in humans.
Imagine a long distance trip to a remote planet.
Even leaving aside the obvious consideration
that you need extra supplies of oxygen,
water and food to keep the astronauts alive on the spacecraft
for many months or even years,
the psychological factor is of huge importance.
Being in a confined space without your home planet Earth in sight
and knowing that, at least in theory,
this could be a one way journey must be tremendously difficult.
Even if you know that your name will hopefully attain immortality.
Hibernation will then provide a way to escape wakeful reality, so to say,
to allow you to be awake only when it is needed, a form of time travel.
And this is not science fiction.
It is what many animals in the wild use hibernation for.
Just think about this, seasonal hibernators like ground squirrel
s may not even know winter exists,
remaining oblivious as they go from one warm season to the next,
probably without even realizing
that they gained, literally gained, several months of their life.
Still, more research is necessary to rule out
possible negative consequences of deep hibernation
on the human body and the brain.
For example, it was discovered that during hibernation or during hypothermia,
some protein molecules in the brain,
[suffer] modification not dissimilar
from those found in the brain of patients with Alzheimer’s disease.
And there is also a regression of synapses,
those contacts between neurons
which they use for communication during hibernation.
But interestingly, both reestablish promptly upon emergence arousal
from hibernation, which makes hibernation
an absolutely fascinating case of brain plasticity.
If you understand how these processes are regulated in hibernating animals,
it can open completely new perspectives on how to treat or slow down
the progression of neurodegeneration in humans.
There is only one problem with this.
We still do not know how to induce hibernation on humans.
And frankly, I’m not even sure we are on the right track with that.
It may not be particularly difficult to induce an artificial
and physiological state of hypometabolism,
for example, by cooling down the body.
Not a big deal. In fact, we already can do it.
But shouldn’t we look for ways on how to enter hibernation spontaneously,
as other animals do? This is the real challenge.
I would like to come back to sleep here.
Yet another fascinating but bizarre state of being.
We are all experts in sleep.
After all, we sleep every night.
You do not need to know what sleep is or how to fall asleep,
we are just programmed to do it.
The philosopher Daniel Dennett would call it competence without comprehension.
Many of us are very good sleepers, I know not everyone.
But why are we so incompetent in hibernating? It's almost embarrassing.
We know that humans can survive severe hypothermia on Mount Everest,
for example, or in ice cold water.
And therapeutic hypothermia is routinely used in heart surgery.
There are primate species that hibernate, and as far as we know,
there is really nothing unique about us humans
that would prevent us from hibernating.
It seems we just forgot how to do it.
Could we revive, bring back to life this ancestral memory?
Perhaps the very idea of actively inducing artificial hibernation
is not really the way to go.
If it is an ancestral default state of being,
then arguably it cannot be induced.
It just happens when conditions are right
I’d like to consider hibernation on a spectrum of states of our organism
in relation to the outside world as depicted on this picture.
On the one extreme is active alert wakefulness
when you are an agent in control of your environment.
You can choose to change it or avoid it to survive.
The strategy is reliable, but it is energetically expensive.
On the other extreme is hibernation, where the organism
is close to the thermal equilibrium with the environment,
as it relinquishes the capacity of maintaining the autonomy from it.
When this happens,
hibernating animals effectively stop existing as independent individuals,
which is a price to pay for saving energy.
So why have we humans have chosen the first strategy?
Emancipation from the environment?
Perhaps we have forgotten how to hibernate,
because we learned how to make fire and build warm shelters.
As a result, we unlearned how to recognize
and interpret environmental signs that were meaningful
and relevant to our ancestors.
Going back to the hamsters I talked about earlier,
it is remarkable that to switch the physiology into a hibernation mode,
all they need is to perceive that days become shorter. This is all they need.
So we humans have completely lost our connection
with the world outside in this respect.
But human hibernation will probably soon become reality.
Indeed, science fiction authors were often good at predicting
or rather inspiring future technologies long before they were developed.
From radio, television, computers to space travel itself.
And there is no doubt that sooner or later
we will achieve a sufficient scientific understanding of hibernation
to be able to induce it safely in humans.
Sooner If funders decide to give more support to our research.
This will be a really big thing and for so many reasons.
In my view, human hibernation is not something
that we should try to achieve just out of curiosity
or even for our immediate benefit,
it is more than that.
Hibernation will enable long distance space travel, for example.
It will help us to better understand
or even find our true place in the universe.
On the other hand, it can give us new insights
into another dimension of our existence on Earth
within each and every one of us.
It is a journey into the unknown
of a very different, perhaps transformative experience.
So are we humans up for a challenge to gain back
the unique capacity to hibernate?
Which other living organisms like this hedgehog just take for granted?
And of course, if we succeed,
it will equip us with all the advantages
that are routinely used by so many animals around us.
So scientists now agree that it is not only about saving energy,
but it is also about surviving climatic catastrophes.
So perhaps it could help us to deal with major natural
or technological disasters we are likely to face in the future.
When in hypometabolic state we need less oxygen,
can better tolerate radiation,
survive low temperatures and food shortage
and likely become more resistant to toxic substances.
What if hibernation becomes for humanity the only certain strategy to survive?
I hope that one day in a not too remote future
hibernation in humans will become possible.
And we will find out what it’s like to hibernate from our own experience.
Thank you very much. (Applause)