I think part of the reason there is so much stigma about sweat
is because it is completely out of our control.
When your body gets the cool down directive you begin to sweat
and there is nothing you can do to stop it.
In this era of curated personalities
on social media, this is particularly stressful.
Evolutionary biologists call our sweating our human superpower.
Your main way of not dying of heat stroke is to sweat.
So, you know, let's dial down the stigma on sweat
and appreciate it for what it's done to keep us alive.
Some of us sweat more than others.
This is both because of genetics and the environment.
You effectively have between two and five million sweat glands on your body.
We are born with all the sweat glands that we will ever have.
But they're not active until our toddler years.
And in those first years of life,
your body is experiencing the environment that you're growing up in
and learning to cue your sweat rates to optimize cooling in that environment.
In fact, athletes do that. As they train more, sweat sooner and faster.
So our bodies do learn to adapt to hotter weather.
And as we, as a species, face climate change,
our sweating may be one of the things that, you know, keeps us alive
in the coming climate apocalypse. If for no other reason,
that's one reason to appreciate the sweating that our bodies do.
Most of our predators and our preys run a lot faster than we do.
We'd go hungry, except they're very furry
and they have to cool down through other strategies.
Meanwhile because we have a huge surface area,
off of which we can continuously cool by sweating and evaporating,
we could just keep running and catch up.
Back in the day, that sweating technique allowed us to survive
and dominate the natural world.
Dogs and many other mammals stick out their tongue
and pant using saliva to evaporate away the heat.
Kangaroos and cats lick themselves.
Other animals like seals pee on themselves.
Pigs cool down by rolling around in mud.
The biggest myth about sweating is that it is a detox method.
And if you understand the basic biology of sweating you'll understand why.
Sweat is actually sourced from the watery parts of blood.
So if you detoxed by sweating,
right, you would have to get all the liquid in your blood out.
That would dehydrate you completely and you would dry up and die.
Instead your body is super smart. It filters your blood
of the bad stuff in the kidneys and dispatches that out in urine.
We actually have two kinds of sweat glands.
The first kind of sweat gland is our evolutionary superpower.
This is the salty, liquidy water that evaporates off our body
and takes our body heat out into the atmosphere.
The other kind of sweat gland appears in armpits at puberty.
And that's the sweat that's responsible for turning armpit into stink zones.
That sweat is not stinky at all when it emerges.
It's actually the bacteria living in and on your body that eat that sweat
and they metabolise it into the stink that leads to our own body odours.
And, you know, we all have a body odour print,
we all smell uniquely and some of us certainly smell more than others.
You have two armpits.
So the way it works is a person, a subject, comes in and
in one armpit they get the product being tested and in the other nothing.
That's the technical term.
[sniffs]
And evaluates the odour intensity
and based on how you smell in one armpit and then the other,
she can say whether a product is you know working.
The first thing that you do is you wipe off all of deodorant
and antiperspirant and perfume that you have put on that day.
And then the organisers take you through a high intensity exercise.
And you effectively work up a sweat.
At that point, you're given a cotton pad.
And then you dab yourself and then that is put into a glass jar.
And then all of those glass jars are put on a table
and everybody sniffs through them.
You're told to pick your top five.
And if, say for example, I picked you in my top five
and you picked me in your top five then it would be a match.
A lot of people have been searching in the body odour that comes out
of your armpits to find something that might explain our attraction to others.
It turns out that forensic chemists can find out all sorts of information
about your health and actually your vices from just one fingerprint.
And fingerprints are just inked in sweat.
You can find out some biomarkers of disease.
Like whether the person at the crime scene has cancer.
We are leaving fingerprints everywhere and so there is concern
that once this technology hits the mainstream
then an employer could go to your desk and find out
if you come to work intoxicated or a health insurer could say:
'It looks like you have a condition or a disease.
We don't want to insure you.'
Ultimately, our sweat tells all of our secrets.
It keeps us alive by cooling us down but it also kind of keeps us honest.