00:00:00
There is this idea floating around that what
doesn’t kill you, makes you stronger.
00:00:05
That surviving a disease leaves you better
off.
00:00:07
And it seems to make sense because we have
all experienced this.
00:00:11
When you go through hardship, often you come
out more resilient, more ready to face a difficult
00:00:15
situation in the future.
00:00:17
But it turns out that sometimes, what doesn’t
kill you makes you weaker.
00:00:22
So, what happens when you get sick?
00:00:34
The Machinery of War
00:00:36
Think of yourself as a large country, with
a sizable army to defend it.
00:00:40
You are surrounded by enemies that want to
take your land, your energy, your resources.
00:00:46
This is a matter of life and death, so your
body evolved to be sensitive to damage and
00:00:50
to the presence of enemies.
00:00:52
Because this means that an invasion might
happen at any moment and that it has to act
00:00:56
fast.
00:00:57
Let us start an invasion and see what happens.
00:01:01
The moment your cells notice that something
is off, they release an onslaught of signal
00:01:06
proteins called cytokines.
00:01:07
They are like air raid sirens that activate
all sorts of immune cells, that then themselves
00:01:13
release many more cytokines, amplifying the
alarm.
00:01:16
Soon you are flooded with signals that trigger
precautions and counter-measures.
00:01:21
Mobilization is under way.
00:01:23
Your brain activates sickness behavior and
reorganizes your body's priorities to defense.
00:01:29
The first thing you notice is that your energy
level drops and you get sleepy.
00:01:33
You feel apathetic, often anxious or down
and you lose your appetite.
00:01:38
Your sensitivity to pain is heightened and
you seek out rest.
00:01:41
All of this serves to save your energy and
reroute it into your immune response.
00:01:47
You become a country under attack switching
into a war economy, because properly activating
00:01:52
your immune system is intensely disruptive
and draining.
00:01:56
Just like war is expensive for a country as
industry switches to building tanks, your
00:02:01
immune system demands huge amounts of energy,
amino acids and micro elements to build its
00:02:06
weapons.
00:02:07
Take fever: it speeds up your metabolism and
makes your cells work harder and faster, while
00:02:12
creating heat that is pretty stressful for
many invaders – but it uses up a lot of
00:02:17
calories to maintain.
00:02:19
Then your immune system begins to clone millions
of specialized immune cells to respond specifically
00:02:24
to the enemy infecting you.
00:02:26
B Cells produce millions of antibodies every
second, each requiring hundreds of amino acids
00:02:31
to construct.
00:02:33
Billions or even trillions of proteins need
to be made to refresh the complement system,
00:02:37
a minefield inside your blood.
00:02:40
Cytokines, the mobilisation and information
signals, also need constant refreshing.
00:02:46
Usually you acquire your resources by eating.
00:02:49
But when you are sick, your body slows down
your digestion because it needs a lot of energy
00:02:53
you can’t spare.
00:02:54
So it reaches for the easiest source of amino
acids and starts breaking down your muscles.
00:03:00
All that muscle that you worked so hard for
is sacrificed to keep you alive.
00:03:06
If you are young and healthy and fit, you
will make up for that quickly once you are
00:03:09
better.
00:03:10
But if you are old or very young, weak or
suffer from chronic illness, this may be way
00:03:15
too draining.
00:03:16
Your body is literally consuming itself to
keep the defense going.
00:03:20
If your whole system is already strained,
when you get sick, just keeping your immune
00:03:24
responses going can overwhelm your capacities.
00:03:28
Your Immune System is a Jerk.
00:03:30
Our enemies too.
00:03:32
Your immune system is as dangerous to you
as it is to enemies.
00:03:36
There is a very fragile balance between the
damage caused by an infection and the collateral
00:03:41
damage caused by immune cells.
00:03:43
One of your first responders are Neutrophils
– imagine crazy aggressive chimps with machine
00:03:48
guns.
00:03:49
If a Neutrophil encounters enemies it showers
them with chemicals that cut them open but
00:03:54
can also damage civilian cells, especially
if the patient is already compromised, for
00:03:59
example by smoking.
00:04:01
On top of that the microorganisms that invade
you often release chemicals and toxins that
00:04:06
can cause significant damage and cell death.
00:04:09
So a serious infection often causes many tiny
wounds, literally holes in your organs.
00:04:15
As you can imagine it is not great to have
holes and wounds in your organs, and your
00:04:19
body rushes to close them.
00:04:21
Your Neutrophils and Macrophages help by releasing
chemicals that signal the body to start repairs,
00:04:27
and most of the damage is quickly filled up
with regrowing cells.
00:04:30
But others are filled with collagen, a sort
of fix-all organic cement that gives your
00:04:35
gooey tissue structural integrity.
00:04:37
You have seen the result on your skin as scars.
00:04:40
A scar is different from the original tissue.
00:04:43
It has no functioning cells in it, it is like
a sloppily applied cement patch.
00:04:47
It can’t do what the original tissue was
doing.
00:04:50
A scar on your heart makes it beat a tiny
bit weaker.
00:04:54
A scar on the lungs no longer captures oxygen.
00:04:57
A scar on your liver makes it a worse filter.
00:05:01
And so, as you go through life and survive
serious disease after serious disease, the
00:05:05
functionality of your organs may decrease.
00:05:07
This damage is usually small enough not to
affect your quality of life – but can be
00:05:13
permanent.
00:05:14
Ok, this sounds depressing, but there is actually
something you can do to avoid a lot of this
00:05:18
damage and train your immune system!
00:05:22
The best way to train your Immune System
00:05:25
Your immune system is unique.
00:05:27
Everyone has a slightly different immune system
that’s stronger against some enemies and
00:05:31
weaker against others.
00:05:32
Which makes evolutionary sense, as this protects
our species from being wiped out by a single
00:05:37
infection.
00:05:38
Collectively, the immune system of the human
species is a spectrum: most people respond
00:05:43
well enough to an infection, a few are super-responders
and a few don't respond well and die.
00:05:49
Some people survived the black death, are
more resistant to HIV or Corona virus or even
00:05:55
resistant against Ebola.
00:05:56
Others are killed easily by the flu or highly
vulnerable to certain bacterial infections.
00:06:02
Where you are on this spectrum is impossible
to predict.
00:06:06
And you also respond differently to every
possible infection.
00:06:10
This is why seemingly very healthy young people
died from Covid while for some elderly people
00:06:15
it was more like a mild flu.
00:06:18
The idea that you can weather all sorts of
diseases if you never get a cold is wrong.
00:06:22
You never know what your immune system is
good at until it is tested.
00:06:27
Getting sick is a gamble in life’s casino
with your health on the line.
00:06:32
Always.
00:06:33
But there is something you can do: hacking
one of the best features of your immune system.
00:06:38
When you survive a disease, usually you have
better defenses against it afterwards – you
00:06:43
gain memory cells that are very good at killing
the specific enemy you fought that day.
00:06:47
So you either don’t get the disease again
or the next infection is much milder.
00:06:52
And you can use an incredible achievement
of human ingenuity that taps into this mechanism
00:06:57
to prevent damage from disease and train your
immune system: Vaccines.
00:07:03
Vaccines basically pretend to be a disease
and train your defenses to be ready if it
00:07:07
ever shows up for real.
00:07:09
The goal is to create the same memory cells
that you would get after surviving an infection.
00:07:14
But if you can feel some side effects, why
should you still do it?
00:07:19
Nature Vs Vaccine Dojo
00:07:22
You have two options to train your immune
system: Vaccine Dojo and nature dojo.
00:07:28
In vaccine dojo you train with paper weapons
and learn to defend yourself.
00:07:33
Sure, you might get a black eye or a bruise.
00:07:37
Sometimes after a vaccine, you get sick for
a few days, but that’s generally it.
00:07:41
No scars, no permanent damage.
00:07:43
We discussed vaccine side effects in detail
in another video if you want to learn more.
00:07:48
On the other hand, getting a disease to become
immune means going to a nature dojo.
00:07:52
In nature dojo, you train with real weapons,
sharp knives and swords.
00:07:58
Things might still work out, but with way
more cuts and wounds.
00:08:02
But from time to time someone will die, be
it a kid from measles or an adult from influenza.
00:08:08
Nature dojo is just way more risky.
00:08:11
On top of that, the immunity you get from
a vaccine is often better than the natural
00:08:15
resistance, because they are engineered to
engage your immune system in a more productive
00:08:20
way.
00:08:21
Of course vaccines are not magic and sometimes
they do not protect us as well as we’d like
00:08:25
them to.
00:08:26
Maybe because an enemy mutates too quickly,
like the Omicron coronavirus, or because your
00:08:31
specific immune system does not respond well
to the vaccine and builds less of a defense.
00:08:36
Still, being vaccinated is one of the best
tools to train your natural defenses.
00:08:42
In the end, if we look at the stunning progress
humanity has made in the last century, eventually
00:08:47
we may overcome disease for good.
00:08:50
But until then we can do our best to take
care of ourselves and others - your body and
00:08:55
your older self will be grateful to you.
00:09:00
Diseases are not the only problem humanity
can address if we work together.
00:09:04
We believe the same is true for climate change,
one of the main challenges of our generation.
00:09:08
We are very passionate about this topic and
we have covered it extensively in previous
00:09:13
videos.
00:09:14
Humanity needs to tackle this problem on different
levels of society, from governments and economies
00:09:18
down to the individual.
00:09:20
And there’s one way you can take action
now – by working with our friends from Wren,
00:09:25
who help you offset your carbon emissions.
00:09:27
By visiting wren.co and answering a few questions
you can find out what your personal carbon
00:09:31
footprint is.
00:09:33
Your first step should be reducing your footprint
– but there are limits to that.
00:09:38
Wren lets you offset the rest of your carbon
footprint with a monthly subscription that
00:09:42
supports projects that plant trees, protect
rainforests, and remove carbon dioxide from
00:09:47
the sky.
00:09:48
We think it's one of many puzzle pieces that
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00:09:50
crisis.
00:09:51
Once you sign up to make a monthly contribution
you’ll get pictures and updates from the
00:09:55
project you support, so you can directly see
the impact you are making.
00:09:59
We appreciate Wren’s focus on transparency
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00:10:04
your money is spent.
00:10:05
One project we find especially interesting
is Refrigerant Destruction — Old refrigerators
00:10:10
use harmful gases as a coolant.
00:10:13
These gases, once released into the atmosphere,
cause global warming thousands of times faster
00:10:17
than CO2.
00:10:18
Wren’s project permanently destroys containers
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00:10:27
Sign up through wren.co/kurzgesagt to start
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As climate change is close to our hearts we
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00:10:40
Continue your kurzgesagt journey into the
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00:10:46
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