Psychological & Physiological Effects Of Caffeine

Caffeine is the most pervasive drug in modern society. It can be found in coffee, tea and soda and chocolate as well as in over-the-counter medications for allergies and pain relief. As a stimulant for the central nervous system, caffeine's affects on alertness and wakefulness are well known. However, caffeine has lesser-known effects on the brain, body and mood.

Elevates Body Processes

People drink caffeinated beverages to stay awake, but the effect on the central nervous system is more wide ranging. Caffeine alkaloids increase body temperature, heart rate and blood pressure, essentially "revving up" the body, similar to the effects physical exercise and stress. Carnegie Mellon University suggests that caffeine can be lethal in high doses, but the quantity required to stop the heart is equivalent to about 80 cups of coffee consumed in a short period of time.

Sharpens Critical Thinking

Meanwhile, the cerebral cortex and the brain stem are put into their own hyper-drive. Caffeine not only increases the metabolism in the brain but also simultaneously lessens cerebral blood flow. This effect, known as a temporary hypoperfusion, can be likened to damming a river during a hurricane. One prominent cognitive effect is heightened "action monitoring," the skill of the higher brain to notice and correct for errors in judgment and mental processing. In a related 2004 study from Brain Research, psychologists from the University of Amsterdam found that just a couple of cups of coffee were needed to significantly improve action monitoring.

Improves Mood

Caffeine has a dramatic effect on mood. While this impression probably is not surprising for coffee drinkers the world over, research on the topic was scant until 2007, when researchers from the University of Western Australia studied the effect of caffeine on the self-perceived mood of students. The students rated their mood after consuming 100 mg of caffeine, compared to a placebo, to be "significantly more awake, clear minded, energetic, alert and anxious," according to their published results in the journal "Advances on Physiology Education."

Heightens Athletic Stamina

The use of caffeine in competitive sports is considered contraband, as positive testing will invalidate a participant in the Olympic Games and other international events. For years, athletes have claimed caffeine increases long-term stamina in sports such as running, cycling and soccer, but is not effective for sports that require short bursts of energy. This view was corroborated in a 2008 study in the journal "Medicine and Science in Sports and Exercise," in which researchers from Canterbury Christ Church University found caffeine increased performance significantly in 40 km cycling events.

Addiction

As with many stimulants, caffeine and caffeine-like alkaloids are physiologically and psychologically addictive. Withdrawal can instigate headaches, muscle cramping and fatigue. Psychological symptoms include grumpiness, inability to focus, depression and anxiety. CNN Medical Correspondent Judy Fortin has reported that 80 to 90 percent of Americans drink caffeinated beverages every day, and half of these would experience withdrawal symptoms if they missed the daily dose. Going "cold turkey" is not recommended. Instead, Fortin's research suggests that weaning yourself slowly and deliberately is the easiest way to reduce caffeine dependency.