How does caffeine make you more alert and work as a cognitive enhancer if it reduces blood flow to the brain?

Question

I’ve just read that a 250mg dose of caffeine can reduce blood flow to the brain by 22%-30%.

It seems counter intuitive to me that a chemical that restricts blood flow to the organ responsible for all mental operations actually improves our mental functioning.

There’s probably a simple answer but 22-30% seems like it would significantly impair the brain’s functioning

In: 129

Answer 1

You will be surprised to know that caffeine causes vasodilation by stimulating the endothelial cells to release nitrix oxide. The vasoconstriction is caused by the catecholamine release also due to caffeine blocking adenosine. There is a lot of constriction and dilation going on because of caffeine. The cognitive benefits are because of increased catecholamines. The reduced blood flow is negligible for the brain as it has mechanisms to compensate, i.e.. by increased uptake of oxygen. However, at low doses, and if you are a frequent drinker, you won’t notice anything.