[Narrator] It's not just you.

Everyone seems to be cold plunging

or watching other people do it.

[cold plunger whooping]

We're going to have cold plunger Josh Cameron

film the process. [ice breaking]

This is what is happening in his body.

[water splashing]

First, the cold shock,

where the cold might just take our breath away.

As soon as you step into the water

you will activate your hyperventilation

[Josh hyperventilating] [water splashing]

and that is because you are not adapted yet.

[Narrator] His body goes into fight or flight mode

from the cold shock.

Every cell in your body is gonna be affected

by this stressor,

which is very potent for you.

[Narrator] Micro-stress might feel painful in the moment,

but it has long-term benefits.

That will help your overall health

by increasing your metabolism

and it will help on your muscles,

on your fat storage,

and it will help on your mental balance.

[Narrator] The skin sends signals to the brain

once the body starts to get cold.

The temperature regulating center sense that,

Wow, this is an emergency.

It will immediately increase noradrenaline in the body

to activate our fight and flight system.

We will have a huge increase by 2.5-fold of noradrenaline

within a few minutes.

[Narrator] Noradrenaline acts on what's called brown fat,

a type of fat tissue that keeps you warm

by breaking down glucose and fat molecules in the body.

It not only activate the brown fat,

it also makes sure that our blood vessels contract

to our arms and legs

so we can keep the warm blood in the center of our body,

because that's gonna save our vital organs.

[Narrator] Activating this brown fat

has long-term benefits.

[Narrator] Scientists saw

that if you can increase your metabolism

by activating the brown fat,

this could actually be a way

to prevent lifestyle diseases such as type 2 diabetes.

The longer time you stay in the water,

the more heat you lose,

and then you have an activation of the muscles.

[Narrator] And the first muscles that start to shiver,

they're located in your chest and legs.

Pectoralis major, which is the breast muscle,

and also the femoralis,

which is the big muscle on your thigh.

And when you feel the muscles are shivering,

it's time to actually get up.

You have reaped all the benefits that you need.

[Narrator] The more times you cold plunge,

the more benefits the body gets.

This includes an increase in dopamine.

This dopamine increase from cold immersion

is just as high as nicotine or cocaine.

Let's go baby.

So this is definitely the most natural high you could get.

Dopamine gives you drive and motivation.

You'll have an increase

of 2.5-fold above baseline of dopamine.

That's not gonna subside just immediately

as soon as you go up.

That will last for hours afterwards.

[Narrator] An increase in serotonin.

So after three times, after four times,

you also activate your vagus tone.

That will give you a sense of mental balance

because it increases serotonin in the the brain.

That is not something you get

from cold showers, for example.

You get that from submerging into cold water.

[Narrator] And an increase in oxytocin.

We have seen that from mice studies,

they have an increase in oxytocin.

And oxytocin is our love drug, natural drug in our brain,

that is increased every time we fall in love,

or we have sex,

or we eat chocolate,

touch and stuff like that.

[Narrator] You don't necessarily

need to dunk your entire body [water splashing]

into cold water

to reap the benefits.

I found this very interesting study from Canada

from a scientists group.

They have calculated how much heat you lose

submerging your body into cold water up to the neck

versus how much heat you lose from also dunking your head.

Submerging up to the neck,

you would lose 11% of heat from the head.

But if you also then do a head dunk,

you will increase that heat loss by 36%.

[Narrator] In fact, dunking your hands

can be just as beneficial.

I found this very interesting study in fishermen.

They work in very cold water

with their hands submerged many hours.

Scientists found they were cold-adapted,

so the cold adaptation doesn't just come

from exposing your full body up to the neck.

You can also expose parts of your body

and you will get a systemic effect.

[Narrator] Finally, the after drop.

You will actually be colder when you get up.

All your muscles will start to shiver

because when you're in the water,

your body is completely trying to shut out the cold

but when you get up,

the blood vessels will dilate

and the warm blood from your core

will flowed out to your fingers

and your cold tissue in your muscles.

In your core, you have receptors

which will send, then, a signal to the brain telling you,

Oh, now the blood has become much colder.

That is a decrease in temperature in your core

and your muscles would then start to shiver even more

because now you got colder.

That is completely normal and just keep moving afterwards.

Just don't sit on your couch.

This principle is called this Soeberg Principle

and it's named by a professor from Stanford University.

[Narrator] Cold plunging is a practice

with a long history with the Egyptians.

This first civilization,

they built the seas and the rivers

and thermal sources around them.

In Egyptian times,

the water was used for hygienic and clinical purposes

[Narrator] And with the Greeks.

Hippocrates said

that because of the imbalances that we have,

the fluids in the body can get stuck

and that imbalance can be restored

going into cold water and warm water.

[Narrator] But researching what happens in the body

and the potential benefits of the cold is recent.

The Titanic actually sunk in April the 15th in 1912

and that was a big disaster,

but this is in history the first time we really know

how much time the body can be in cold water

before it gets hypothermic.

From that on, people were thinking,

Whoa, cold water could actually be really dangerous.

It didn't really get any better

when we jump right on to World War II,

where Nazi experiments were performed

in the concentration camps in Dachau

to investigate how long a human body could be cooled

before they died.

It has taken decades before scientists started again,

investigating human physiology and cold water.

In the sixties and seventies,

we begin, again, to see studies where we can see

what happens when you put people into cold water.

[Narrator] Cold plunging weekly

can have many long-term benefits.

Another long-term benefits of going into the cold water

is the increase in metabolism.

Just by 11 minutes per week divided on two to three days,

you will have an increase in thermogenesis in the body

so you'll get warmer,

you will get a increased insulin sensitivity,

and you will have a better glucose balance,

meaning that you will easier

get rid of the glucose in your bloodstream

when you are adapted to cold water.

[Narrator] The same study

by Dr. Soeberg and her colleagues

suggests adding warmth.

We also saw that going into a sauna,

57 minutes divided on two to three days,

10 to 15 minutes at a time,

you can also increase your metabolism

and you will lower your core temperature

which is a good thing,

because then you have a higher threshold

for getting hypothermic as well.

[water splashing]

The long-term benefits of cold plunging seems to be

that you will have

a better temperature regulation in your body.

You will become a warmer person physically.

Apparently, also emotionally.

That could explain the culture

that is also in the winter swimming clubs,

that people get this gratitude

because they have, maybe, this large increase in oxytocin.

I think it explains why we see

that kind of friendly atmosphere there.

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