Rachel Lance

The deeper we go, the more that pressure increases simply from the weight of that water pushing down.

That's the million dollar question, isn't it?

Basically, the human lungs are very weak.

They're not a strong organ.

And so they're really good at what they do in terms of processing gas, but they do it passively.

So they essentially just let that gas flow come in and out of the body.

What that means for breathing is that when we breathe a gas, we have to breathe the gas of the approximately same pressure as the air around us or the water around us.

When you're underwater, that means you're breathing high-pressure gas.

That means that that increased pressure can help those gases absorb into your bodily tissues.

The air around us is about 78% to 79% nitrogen.

So as we're underwater and we're breathing that higher-pressurized gas, that nitrogen and the other gases absorb into our tissues.

What you described with decompression sickness, the bends, that's when we come back up.

We go to those reduced pressures too quickly.

The nitrogen comes out instead of harmlessly in the bloodstream processed by the lungs.

It comes out as bubbles.

That's really bad.

It causes all kinds of physiological issues.

In the most extreme manifestations, you can get bubbles everywhere.

There are case reports of bubbles in the brain and bubbles in the spinal cord, bubbles in the liver and in the joints.

Those are the extreme cases.