 |
CAFFEINE
|
WHAT IS CAFFEINE?
| Many people think of
caffeine as something in coffee. It is also found in many other common
substances. These include: tea, cocoa, chocolate and cola. Caffeine is
defined as a drug because it affects the central nervous system. It is
categorised as a stimulant drug because caffeine speeds up production
of nerve impulses. Scientists first separated caffeine from coffee in
1820. In its pure form, it consists of bitter tasting white crystals. The amount of caffeine in a product depends on both the substance and on the way it is prepared. In coffee beans, caffeine content will depend on the strain of the coffee plant: the Arabic strain contains about one per cent caffeine and is grown in Central and South America, the Robusta strain contains about two per cent caffeine and is grown in Africa and Indonesia. In tea, the caffeine content depends on the strength of the brew. Caffeine content in tea can be as high as five per cent. The caffeine content in a cup of coffee, however, is usually higher than tea. This is because it takes a lot more coffee beans to make a cup of coffee than tea leaves to make a cup of tea. |
EFFECTS OF CAFFEINE
 In
small doses (such as a cup of coffee), caffeine:* Increases general metabolism and body temperature * Increases urination * Increases alertness * Stimulates the secretion of gastric acid. In large doses, caffeine can produce (especially in non-users) headaches, jitters, nervousness and even delirium. In very large doses (l0g or more), caffeine can produce high blood sugar and urinary acid levels. |
LONG TERM EFFECTS
 There is no evidence of caffeine producing any toxic effects if consumption is below 600mg a day. Consumption above this level may cause insomnia, anxiety, depression and stomach upsets. |
CAFFEINE AND SLEEP
| When caffeine is taken before going
to bed, it usually: * Delays and shortens sleep * Reduces the deep sleep cycle * Increases the amount of dream sleep early in the night, but reduces it overall |
