Andrew Huberman

waiting at the interstitial space and at the interface between this arterial system that delivers oxygenated blood and the venous system of capillaries that collects the deoxygenated blood and all these waste products.

And it's right there as a series of tubes ready to catch the excess fluid and the waste products and bring them back to the heart also

but to do a lot of really important things with them along the way.

You might say, why would you have this third system, right?

The circulatory system for blood sounds nearly perfect.

And the key is it's not perfect.

Your lymphatic system is responsible for taking the fluid that remains in the extracellular space and all the gunk, all the waste products from cellular metabolism, again, proteins, ammonia, carbon dioxide, and bringing that back into the circulatory system of blood.

But along the way, doing a number of very important things, including checking it out to see whether or not there are any contaminants, right?

Any infections, bacterial or viral infections.

That occurs in structures called the lymph nodes, which you've probably heard of and we will return to a little bit later.

But leaving aside the immune surveillance role of the lymphatic system, just the mere role of needing to clear away what really is about three to four liters of excess fluid in the interstitial space is so important.

You might say, well, how important can it really be?

Right.

Three or four liters.

Is it really that important?

It is absolutely crucial.

Why?

Because if too much fluid and amino acids and cellular waste products build up in the tissues that are using the oxygenated blood and need all the nutrients,

that is ripe for infection, right?

Bacteria love to grow in warm environments with lots of amino acids.