If you want a healthy brain stay away from caffeine. Large doses of caffeine constricts blood flow to the brain and many other organs. A little caffeine a day is probably not a problem, but more than a cup or two can certainly be trouble.
New coffee shops seem to spring up on every street corner every day, selling highly caffeinated drinks full of sugar and fat. As a society we are going from one to two cups a day to one or two cups three or four times a day.
Understanding the drug’s actions will help understand why we consume so much caffeine and why we should significantly curb our use.
Adenosine, a chemical in the brain that causes drowsiness by slowing down nerve cell activity, is a key to understanding caffeine addiction. When we are tired adenosine triggers the brain to slow down so we will go to sleep and naturally rejuvenate brain function. The purpose of sleep is to replenish certain chemicals in the brain to help with efficient nerve cell firing. Adenosine tells us when we need to sleep.
Caffeine blocks the effects of adenosine by occupying the adenosine receptor sites and preventing the brain from seeing it. So even if you are tired and are in need of sleep to rejuvenate your brain chemistry, caffeine tricks the brain into thinking it is wide awake.
We are a sleep deprived nation and caffeine addiction is a leading cause. Caffeine, a stimulant, causes the release of adrenalin from the adrenal glands, putting the body into a fight-or-flight mode, where the pupils dilate, the heart beats faster, blood vessels on the skin surface constrict to slow blood flow from cuts and also increase blood flow to muscles … blood pressure rises, blood blow to the stomach slows, the liver releases sugar into the bloodstream for extra energy, and muscles tighten up, ready for action. Caffeine puts us in a ready state for trouble.