The coffee has a refreshing effect which is due to the basic ingredient, caffeine, an alkaloid compound found in the seeds of the fruit. It is estimated that the beverage preparation process is repeated worldwide over 400 billion times a year.
The most common effect of coffee relates to the central nervous system. In reasonable quantities, coffee improves mental abilities, as it causes alertness and reduce boredom. The main reason is that it contains caffeine, an alkaloid that acts as a stimulant. For this reason coffee is usually consumed in the morning or during labor. More sensitive to the action of caffeine is the elderly, especially with regard to sleep. Instead, children are more vulnerable than adults, in small doses of coffee. Often, pupils and students maintain their attention to the many hours reading that require examination, by means of coffee.
In the human brain, caffeine causes constriction of vessels, while the peripheral vessels, dilation. It is not accidentally use in several drugs for combating migraine.