Caffeine, also chemically known as 1,3,7-trimethylxanthine, is one of the most popular central nervous stimulant that is used and studied by people all over the world. It is estimated that the average American consumes about 300 mg of caffeine daily. Caffeine is found in tea, cocoa, chocolate, and coffee. The influence of caffeine on the nervous system is seen through its powerful effects on one’s cognition and behavior in desirable and undesirable ways.
The effects of caffeine on the nervous system derive from its interaction with the adenosine receptors at multiple sites in the brain. When adenosine binds to neural receptors, brain activity decreases, which causes the blood vessels to dilate and heart rate to slow down. Since caffeine is chemically similar to adenosine, caffeine binds to the same receptors that adenosine normally binds to. As a result, caffeine blocks adenosine because the cell can no longer identify adenosine because the lack of available receptors. This increases brain activity, which boosts mental concentration and neuro-muscular movement and reduces sleep behavior and feelings of fatigue. This new activity stimulates the pituitary gland, which then produce hormones that notify the adrenal glands to release adrenaline, or epinephrine. The influx of adrenaline notifies other parts of the body, such as the liver, to increase energy by releasing more amounts of sugar into the bloodstream. By increasing adrenaline levels, caffeine also helps mobilize free fatty acids from fat and intramuscular triglycerides. This leads to an increase in fat oxidation and glycogen in muscles, which can positively impact one’s athletic performance. Therefore, the effects of caffeine are greatly appealing to those with demanding lifestyles and workload, such as students and workers.
A research study led by Daniel Borota in Johns Hopkins University demonstrates that caffeine has many health benefits, such as the improvement of long term memory and the enhancement of one’s cognition. During this experiment, 150 participants were asked to identify pictures of objects as ‘indoor’ or ‘outdoor’ items. After identifying, participants were randomly given a placebo tablet or a 200 mg of caffeine in a form of a pill. The next day, the participants were asked to perform a similar task, which they were all able to do. However, the results of this experiment concluded that the subjects who consumed caffeine were better at identifying pictures than those who took the placebo tablet as seen in the diagram below.
After conducting this experiment, the researchers continued to study the correlation between the amount of caffeine taken and the one’s memorization abilities. The study concluded that the performance of those who took 300 mg of caffeine was better than that of those of those who took the 100 mg dose. However, there was no improvement for those who took doses greater than 300 mg. Accordingly, they established their new proposition that in order to see improvements in memory, one needs to take at least 200 mg of caffeine.
In addition, caffeine also impacts the works of dopamine, a neurotransmitter, as a result of its blockade of adenosine receptors. Caffeine increases dopamine levels, which can improve one’s mood, in the prefrontal cortex. Due to the fact that the prefrontal cortex is the main site involved with reward and addiction, caffeine can also encourage people to become physically and psychologically dependent on it. Hence, excessive amounts of caffeine can result in withdrawal symptoms and caffeine intoxication. Withdrawal symptoms, include irritability and drowsiness, tend to appear to those who have stop consuming caffeine for two days following an average intake of 235 mg daily. In consequence, withdrawal symptoms can negatively influence one’s academic and athletic performance. On the other hand, studies show evidence that dopamine can protect brain cells from age and deterioration from disease.
In addition, having an overdose in the amount of caffeine consumed can result in a state of caffeine intoxication, which is when the central nervous system is over-stimulated. This situation typically occurs after one has consumed more than 400 mg of caffeine in one sitting. The effects of caffeine intoxication heavily impact the nervous system. Studies show a positive correlation between the amount of caffeine taken and the levels of anxiety, insomnia, muscle-twitching, and rhabdomyolysis, the breakdown of skeletal muscle tissue. Since caffeine is a stimulant that increases heart rate, it can also increase levels of nervousness and agitation as well as anxiety levels. In extreme cases, caffeine intoxication can lead to death.
Due to its fat solubility, caffeine is quickly absorbed and carried by the bloodstream throughout the body. Thus, caffeine has the ability to increase mental abilities, emotional stability, and physical performance by sharpening memory, enhancing mood, and improving motor movements. However, high doses of caffeine can bring negative effects to the nervous system. These effects include withdrawal, caffeine intoxication, and an increase in psychiatric disorders. All in all, caffeine proves to be powerful stimulant that does not only influence the nervous system, but the entire body.
...(download the rest of the essay above)