Caffeine occurs naturally in coffee and cocoa beans, kola nuts and tealeaves. It is a key ingredient of cola drinks, chocolate, many non-prescription medications and even dietary and sport supplements.
Caffeine acts as a mild central nervous system stimulant - so it provides an initial boost of energy, keeps us alert and prevents fatigue. Our main sources of it are coffee, tea and soft drinks.
A moderate amount of caffeine per day, approximately 300 milligrams, is relatively harmless for most people. Excessive caffeine can give you the shakes, lead to anxiety, upset your tummy, and keep you from sleeping. A recent study (Pediatrics, 2003) suggests that drinking too many caffeinated soft drinks might be preventing some adolescents from getting a good night's sleep. This is a good enough reason for some parents to insist that their children's schools should not have soft drink vending machines.
Some individuals may be sensitive to the effects of caffeine at very small doses, and pregnancy and aging can affect this sensitivity. So these people should be careful with their intake. Caffeine is an ingredient in more than 1000 over-the-counter drugs, as well as prescription drugs. Read product labels and ask your pharmacist if you are concerned about caffeine intake.
What are the Effects of Caffeine on My Body?
Scientific studies have noted that in small to moderate amounts (50-300 mg) caffeine acts as a mild central nervous system stimulant by increasing the heart rate and blood pressure - so it provides an initial boost of energy, keeps us alert and prevents fatigue. Athletes have taken advantage of this energy boosting effect of caffeine for years - to the point that caffeine's well recognized stimulant effects have put it on the list of banned drugs.