CAFFEINE
More than 80 percent of all adult Americans consume caffeine-containing foods and beverages everyday. The average intake—280 milligrams a day—is about the amount found in three cups of coffee, six cups of tea, or eight cans of soda. Despite its widespread use, however, caffeine’s physiological and behavioral effects are still controversial.
Caffeine stimulates the central nervous system, and taken in large amounts can increase heart rate and blood pressure. At lower doses, 100 to 300 milligrams, caffeine has the ability to increase alertness, boos energy levels and improve mood. Doses above 400 milligrams tend to produce negative effects like anxiety and nervousness, though there have been some cases where people have reacted this way to doses as low as 200 milligrams.
Feeling a caffeine boost doesn’t take long either. Usually it happens within 30 to 60 minutes after ingestion, when concentration peaks in the bloodstream. In addition, clearance time is slow. It typically takes four to six hours for caffeine’s effects to wear off. That’s why many people find it difficult to fall asleep after having an evening cup of coffee.
CAFFEINE BUZZ
Keep in mind there is a difference between being alert and being sober. Contrary to popular belief, coffee or caffeine does not reduce the effects of alcohol or sober someone who is drunk. At best, it will only keep a drunk person wide awake.
CAFFEINE AS A MOOD-ALTERING DRUG
Caffeine is a drug. In some people it can be very positive, making you feel alert and full of energy; in others it creates tension and anxiety, sometimes known as the coffee jitters. And like almost all drugs, caffeine is addictive.
Going cold turkey can lead to headache, fatigue, lethargy, muscle pain and overall bad mood. In some cases, headaches can be so sever they disrupt normal activity. If you want to cut caffeine out of your diet, cut back slowly to avoid these uncomfortable side effects. If you feel a caffeine headache coming on, take a few sips of coffee or cola to relieve the pain. Also be aware that caffeine is found not only in coffee, tea, chocolate and cola but in some over-the-counter pain relievers, cold preparations and sleep suppressants.
Part of the problem behind determining caffeine’s potency is that no one knows just how much or what kind of effect caffeine will have. Sensitivity to caffeine varies greatly from individual to individual. Age (older people are more sensitive to caffeine than younger ones), medical condition, regularity of use and physical state during consumption all influence caffeine’s effects.
People can also develop a tolerance for caffeine, so while two cups of coffee wouldn’t effect a four- or five-cup-a-day drinker, it could make a nondrinker bounce off the walls.
CAN CAFFEINE IMPROVE ATHLETIC PERFORMANCE?
Not only can caffeine rev up the body and increase alertness, it can also speed up reaction times for certain tasks. For well-trained athletes, these beneficial side effects can improve athletic performance. For this reason, caffeine is listed as a restricted substance by the International Olympic committee. Though the extent of its benefits are controversial, caffeine is believed to enhance performance of endurance athletes (runners or cyclists) by sparing muscle glycogen, the kind of energy stored in muscle. Another theory is that caffeine releases endorphins that modify the perception of pain. It has no affect on short-term, high-intensity exercise.
WHAT’S IN A CUP?
Although coffee is the most concentrated source of caffeine in the American diet, it is also found naturally in tea and cocoa. As a food additive, it is added to some soft drinks, over-the-counter and prescription drugs and diet aids.
COMMON FOODS AND BEVERAGES CONTIANING CAFFEINE
Item Caffeine (mg)
6 ounces drip brewed coffee 100
6 ounces instant coffee 70
6 ounces tea 50
12 ounces cola soft drinks 36
1 ounce solid milk chocolate 6
1 ounce solid dark chocolate 20
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