a grizzly bear with the head of a great white shark and cobras for arms,

your body would start releasing adrenaline and norepinephrine within seconds

to prepare you to fight… Or more likely, to take flight.

After a minute or two your body would be flooded with cortisol.

Cortisol is vital in keeping you healthy in tense situations.

But when you stay stressed for too long

it can have the opposite effect.

Cortisol's job is to restore some order to your body.

It puts more glucose into your bloodstream

so you don't crash when the adrenaline is gone.

It also kicks your liver into gear,

pumping out the extra glucose that's now sloshing around inside you.

Our bodies' hormone responses might have evolved when we were battling for survival against predators like bear-snake-sharks.

These days, sources of stress are much different:

dwindling bank accounts, overdue assignments, too much e-mail.

That kind of stress tends not to go away,

which means cortisol levels can stay elevated.

And that can lead to health problems.

Cortisol inhibits some of your immune responses,

meaning you're more likely to get sick and it can take longer for wounds to heal.

Cortisol also slows bone growth, meaning sustained levels can lead to weaker, more fragile bones.

And because cortisol acts on parts of your brain that control appetite,

it also increases your desire for fatty and sugary foods.

Stress eating is real, people!

Here's a weird plot twist for cortisol, though.

That lowered immune response can actually be beneficial.

In its medical form, cortisol is called hydrocortisone.

You may have applied it to a rash or a bug bite,

because it helps reduce swelling and itching –

which is how our immune system responds to certain threats.

So at least you won't have to stress out about that weird rash, which you should probably get looked at. Seriously.

But before you do that.

Hit that subscribe button.

Want to beat stress?

Then eat healthy food, get exercise, get more sleep.

But definitely subscribe.

Thanks to CAS (Chemical Abstract Service) for sponsoring this video.

And hey, if you‚ are really into molecules,

check out the Scifinder Future Leaders in Chemistry Program.

Ph.D. students and postdocs like me from around the world

are brought in to share their insights and go behind the scenes with Scifinder.

It's an all-expense-paid trip where you can get to see firsthand

how CAS builds and maintains the world most authoritative chemistry databases.

You'll also get to travel to the American Chemical Society's National Meeting Exposition.

For details, please visit CAS.ORG/FUTURELEADERS.