If you're not good for anything until you've had your morning coffee, don't blame the beans -- it's the caffeine. You're not alone -- caffeine is the most widely used drug in the world, and most people don't even realize it's a drug. The reason it wakes you up and makes you feel more alert and focused is because it stimulates your central nervous system.
Coffee and Caffeine
Coffee is by no means the only form of caffeine -- it's in tea, soda and even chocolate. But coffee is the most popular caffeine vehicle in the country, supplying over two-thirds of the American caffeine intake. Your average cup of joe may contain up to 220 mg per cup, which is more than enough to pack a whallop once it's absorbed into your bloodstream, usually within about 15 minutes.
Caffeine and the Brain
When the caffeine enters your bloodstream, it makes its way to your brain. Caffeine is a type of xanthine, so it is very similar to adenosine, a xanthine found in your brain. When the caffeine arrives to your brain, it pushes the adenosine aside and binds with the receptors specifically made for the adenosine -- because it's so chemically similar, the receptor accepts it without a problem. This leaves free adenosine with nowhere to go, and your body begins to panic. Your brain immediately kicks into high gear, and starts relaying "emergency" signals throughout your body.
The first signal goes to your adrenal gland, which initiates the "fight or flight" preparations. Adrenaline is released into the bloodstream, triggering a similar response in the cardiovascular system, which begins pumping more blood per beat and faster in order to move blood to the muscles more efficiently. Tissue near the heart produces the chemical norepinephrine that makes your muscles contract harder and more quickly, and your blood pressure rises. This is your body preparing to either stand and fight or run very quickly, but if you don't use either option, these preparations get channeled into focus and attention.
Your body is primed for action, and you're sitting still at the computer. But your body still takes advantage of the increased blood flow, more rapid firing of neurotransmitters and increased blood oxygen levels to help you think. Although thinking is not an outwardly physical display, it requires a flurry of electrical activity in the brain, and your body's "fight or flight" response helps it happen more quickly and efficiently. If you use sugar in your coffee, you may even experience an increase in blood glucose that can make you feel physically energized and ready to work. The end result is that a simple cup of ground bean-wash can clear the fuzzies from your head and keep you focused on the task at hand.
- MedScape: Neurologic Effects of Caffeine
- "Scientific American"; How Does Caffeine Affect the Body?; Neal Smatresk; Feb. 15, 1999
- "Brain Research"; Caffeine and the Central Nervous System: Mechanisms of Action, Biochemical, Metabolic and Psychostimulant Effects; Nehlig A, et al.; May-Aug 1992
- University of Washington: Caffeine