The Facts About Caffeine

By far our most popular (and least harmful) addictive drug, caffeine is the stimulant in coffee, tea, chocolate and cola soft drinks; it is also added to some painkillers, cold medications, weight-loss supplements and drugs used to promote mental alertness.

Within a few minutes after caffeine is ingested, it is absorbed from the small intestine into the bloodstream and carried to all the body’s organs. It speeds the heart rate, stimulates the central nervous system, increases the flow of urine and the production of digestive acids and relaxes smooth muscles, such as those that control the blood vessels and the airways.

Although caffeine in moderation is generally harmless, sudden withdrawal can often cause headaches, irritability and other symptoms that vary in severity from one person to another. For example, in some people who are sensitive to caffeine, the substance can trigger migraine headaches, while in others it might actually abort a migraine by relaxing the constricted blood vessels that are causing the throbbing head pain.

People with some types of heart-valve disease are very often advised to forgo caffeine altogether because it can provoke heart palpitations or other cardiac arrhythmias.

A known performance enhancer

The stimulant in caffeine enhances mental performance by increasing alertness and the ability to concentrate. For many people a cup of coffee helps them ‘get going’ in the morning, and coffee or tea breaks during the day give them a boost when energy lags.

Athletes have long observed that one or two caffeine drinks an hour before competition can improve performance, especially in endurance sports like distance running.