This post comes from Robert Krakoff, founder of Mind-FX.com, based on the book, Making a Good Brain Great, by Daniel Amen.
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.
Caffeine also increases dopamine levels in the same way that amphetamines do. Dopamine is a neurotransmitter that, in certain parts of the brain, activates the pleasure center. Obviously, caffeine’s effect is much less than that of amphetamines, but the mechanism is similar. The dopamine/pleasure center connection may contribute to the caffeine addiction.
It is easy to see why your body likes caffeine in the short term, especially if you are sleep deprived and need to stay active. Caffeine blocks adenosine receptors, so you feel alert. It raises adrenaline in your body, giving you a temporary boost. And it raises dopamine production to make you feel good. The problem with caffeine is that it leads to a downhill spiral. Once the effects wear off, you feel fatigued and depressed. So you take more caffeine to get going again.
As you might think, having your body in a constant state of readiness isn’t very healthy, and you tend to feel jumpy and irritable. The most important long-term problem is the effect caffeine has on sleep. As we stated, adenosine is important to sleep, especially to deep sleep.
Significant caffeine consumption can prevent you from falling and staying asleep. Sleep deficits add up quickly, so the next day you feel worse and need caffeine (again) to get you jump started. This cycle continues day after day. Like other drugs of abuse, once you get in the cycle, you have to keep taking the drug. Even worse, if you try to quit, you get very tired, depressed and you get a terrible splitting headache. These negative effects force you back to caffeine even if you want to stop.
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