Why Does Caffeine Block Sleepiness Instead of Raising It?

On Huberman Lab, caffeine latches onto adenosine receptors and blocks them. Caffeine does not activate the receptors. Activating the receptors would dial up sleepiness. Caffeine does the opposite.

Subjective sleepiness usually follows a linear process, or probably sits closer to an exponential. Sampling the brain every couple of minutes and asking how sleepy someone feels has not been done in humans the way animal studies siphon samples. Caffeine comes into the system, competes with adenosine, forces adenosine out of the way, hijacks the receptor by latching onto it, and blocks the receptor. Caffeine does not inactivate the receptor and does not activate the receptor. It functionally inactivates the receptor by taking the receptor out of the game for adenosine.