Caffeine is the most commonplace drug used worldwide. Whether it is in coffee, tea, soft drinks, energy drinks, chocolate or in tablet form, caffeine is easily accessed by people of all ages in virtually every culture. Caffeine belongs to the group of medicines called central nervous system stimulants. It is used to help restore mental alertness when unusual tiredness or weakness or drowsiness occurs. Caffeine is the world's most widely consumed psychoactive substance, but unlike most other psychoactive substances, it is legal and unregulated in nearly all jurisdictions.
Caffeine's use as an alertness aid should be only occasional. It can be used to combat sleepiness as in the case of those who work graveyard shifts or simply as a stimulant to wake one up in the morning, quick-starting the metabolism and helping one focus on the tasks at hand.
Caffeine can also be used as a medication to help treat other conditions. When combined with other drugs, it can be used to combat cluster headaches and intense migraines. It can also be combined with pain-relieving medications to help increase the effectiveness up to 40% and increase their absorbency. In premature infants, caffeine in monitored doses can help with breathing problems and in combination with a nutrition and exercise program, can help to curb one's appetite and reduce hunger. There are many causes to use caffeine but the most widespread use of the drug is as a stimulant to help fight fatigue and sleepiness, aiding one in the morning and speeding up one's metabolism.
Consumption of caffeine does not eliminate the need for sleep: it only temporarily reduces the sensation of being tired and the amount of caffeine needed to produce effects varies from person to person and those who regularly use caffeine as a stimulant need increasingly more caffeine to produce the same effects. This is because caffeine is an antagonist for adenosine, a neurotransmitter in the central nervous system. Individuals who regularly consume caffeine adapt to the continual presence of caffeine in the system by increasing the number of adenosine receptors, thus increasing the tolerance to caffeine.
Caffeine is proven to improve both mental and physical performance. Mentally, caffeine stimulates the brain and helps one to focus and concentrate, increasing work productivity and learning capacity. It can also increase the capacity for physical performance, enabling athletes to increase their speed or energy during physical activity.
However the stimulant effects of caffeine are not without side-effects. Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, they may be more likely to occur if caffeine is taken in large doses or more often than recommended. Common side effects of caffeine intake include dizziness, an increased heartbeat, dry mouth, loss of appetite, nausea, nervousness, insomnia, or unusual tiredness as the caffeine wears away. Caffeine can also act as a diuretic causing frequent urination which can also lead to a feeling of being more thirsty than usual. Although small amounts of caffeine can increase concentration and help one to focus and increase productivity, caffeine in large or concentrated doses can also have the effects of jitteriness, shakes, tremors, irritability and nervousness.
Caffeine has a half-life of six hours meaning that only after six hours, only half of the initial dose of caffeine remains in the system. During this time, many people experience headaches as the blood vessels in the head begin to expand as the caffeine wears off. This headache, well known among coffee drinkers, usually lasts from one to five days, and can be alleviated with analgesics such as aspirin. It is also alleviated with simply taking more caffeine. Reduced catecholamine activity may cause feelings of fatigue and drowsiness. A reduction in serotonin levels when caffeine use is stopped can cause anxiety, irritability, inability to concentrate and diminished motivation to initiate or to complete daily tasks. Tremors and shakiness are also most apparent during this stage and side effects such as dry mouth and a sudden appetite often accompany caffeine withdrawal. Regular caffeine consumption reduces sensitivity to caffeine.
Typically, caffeine is consumed without intention. A coffee in the morning, an ice tea for lunch, soda pop in the afternoon with some chocolate can be common ways to consume caffeine on a daily basis without giving second thoughts to the side-effects it may have on one's health. Caffeine in energy drinks is often mixed with alcoholic drinks allowing party-goers to caffinate themselves and stay up late into the night without any tiredness or fatigue. Children many times consume large doses of caffeine through soda and combined with the high sugar levels in these drinks, have sudden rushes of energy and "highs." These can result in moodiness and irritability during the caffeine and sugar withdrawal, drawing criticism from parents who are against vending machines at schools that sell soda. But caffeine is relatively mild as a stimulant and as long as it is taken in moderation with respect to its inherent side-effects and avoiding high doses in short periods of time, caffeine can be beneficial for increasing one's alertness and helping mental and physical performance.
Bealer, Bonnie K., and Bennett Alan Weinberg. The World of Caffeine: The Science and Culture of the World's Most Popular Drug. New York: Routledge, 2002.
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Cherniske, Stephen. Caffeine Blues: Wake Up to the Hidden Dangers of America's #1 Drug. New York: Warner Books, 1998.
Owen, Daniel. "Caffeine FAQ | Coffee and Caffeine FAQ." Coffee and Caffeine FAQ. 15 Jan. 2006. 29 June 2008 .
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