Hi there, it's Matt here and welcome back to the podcast.

Two questions to start with.

Why will you get tired this evening? And why tomorrow morning when you wake

up will you be free from that tiredness? Well, it turns out that there are two independent

but very complimentary forces that explain exactly why this is the case.

The first of those is called sleep pressure and the second is called your circadian rhythm.

Today we're going to focus on the first of those two things.

We're going to focus on sleep pressure because from the moment that you woke up this morning a chemical has been

building up in your brain and the longer that you're awake the more of that

chemical will continue to build up and the more of that chemical that builds up, the sleepier you will feel.

This is what we call sleep pressure. And that chemical is called adenosine.

And you can think of adenosine almost like a chemical barometer

that continually registers the amount of elapsed time since you woke up this morning. So it's a chemical signal that helps tell

your brain and your body how long that you've been awake and when those levels

get high enough it will tell your brain it's time to go to bed because you're sleepy.

Now, Adena scene accomplishes this sleepiness using a very clever dual action effect.

High levels of Adenosine in the evening will

simultaneously turn down the volume in wake-promoting regions of your brain and it will crank up the dial on sleep-inducing regions of the brain.

And at that point with adenosine concentrations peaking, there should be an irresistible urge for slumber that will take hold of you.

And it happens to most of us somewhere after about 12 to 16 hours of being awake.

You can, however, artificially mute the sleep signal of a denizenicine by using another chemical that makes you feel more alert and more awake.

You know this chemical, it's called caffeine.

...