Caffeine

It's 11:00 PM and you've already had a full day of school and after-school activities. You're tired and you know you could use some sleep, but you still haven't finished your homework or watched the movie that's due back tomorrow. So instead of catching a few ZZZs, you reach for the remote - and the caffeine.

What Is Caffeine?

Caffeine is a drug that is naturally produced in the leaves and seeds of many plants. It's also produced artificially and added to certain foods. It's part of the same group of drugs sometimes used to treat asthma.

Caffeine is defined as a drug because it stimulates the central nervous system, causing increased heart rate and alertness. Most people who are sensitive to caffeine experience a temporary increase in energy and elevation in mood.

Caffeine is in tea leaves, coffee beans, chocolate, many soft drinks, pain relievers, and other over-the-counter pills. In its natural form, caffeine tastes very bitter. But most caffeinated drinks have gone through enough processing to camouflage the bitter taste. Most teens get the majority of their caffeine intake through soft drinks, which can also have added sugar and artificial flavors.

Got the Jitters?

If taken in moderate amounts (like a single can of soda or cup of coffee), many people feel that caffeine increases their mental alertness. Higher doses of caffeine can cause anxiety, dizziness, headaches, and the jitters and can interfere with normal sleep, though. And very high doses of caffeine - like taking a whole box of alertness pills - would be harmful to the body.

Caffeine is addictive and may cause withdrawal symptoms for those who abruptly stop consuming it. These include severe headaches, muscle aches, temporary depression, and irritability. Although scientists once worried that caffeine could stunt growth, this concern is not supported by research.

Caffeine sensitivity refers to the amount of caffeine that will produce an effect in someone. This amount varies from person to person. On average, the smaller the person, the less caffeine necessary to produce side effects. However, caffeine sensitivity is most affected by the amount of daily caffeine use. People who regularly drink beverages containing caffeine soon develop a reduced sensitivity to caffeine. This means they require higher doses of caffeine to achieve the same effects as someone who doesn't drink caffeinated drinks every day. In short, the more caffeine you take in, the more caffeine you'll need to feel the same effects.

Caffeine moves through the body within a few hours after it's consumed and is then passed through the urine. It's not stored in the body, but you may feel its effects for up to 6 hours if you're sensitive to it.

Although you may think you're getting plenty of liquids when you drink caffeinated beverages, caffeine works against the body in two ways: It has a mild dehydrating effect because it increases the need to urinate. And large amounts of caffeine may cause the body to lose calcium and potassium, causing sore muscles and delayed recovery times after exercise.

Caffeine has health risks for certain users. Small children are more sensitive to caffeine because they have not been exposed to it as much as older children or adults. Pregnant women or nursing mothers should consider decreasing their caffeine intake, although in small or moderate amounts there is no evidence that it causes a problem for the baby. Caffeine can aggravate heart problems or nervous disorders, and some teens may not be aware that they're at risk.

Moderation Is the Key

Although the effects of caffeine vary from one person to the next, doctors recommend that people should consume no more than about 100 milligrams (mg) of caffeine daily. That might sound like a lot, but one espresso contains about 100 milligrams of caffeine! The following chart includes common caffeinated products and the amounts of caffeine they contain:

Cutting Back

If you're taking in too much caffeine, you may want to cut back. Kicking the caffeine habit is never easy, and the best way is to cut back slowly. Otherwise you could get headaches and feel achy, depressed, or lousy.

Try cutting your intake by substituting noncaffeinated drinks for caffeinated sodas and coffee. Examples include water, caffeine-free sodas, and caffeine-free teas. Keep track of how many caffeinated drinks you have each day, and substitute one drink per week with a caffeine-free alternative until you've gotten below the 100-milligram mark.

As you cut back on the amount of caffeine you consume, you may find yourself feeling tired. Your best bet is to hit the sack, not the sodas: It's just your body's way of telling you it needs more rest. Your energy levels will return to normal in a few days.

Updated and reviewed by: Barbara P. Homeier, MD
Date reviewed: September 2004
Originally reviewed by: Jessica Donze Black, RD, CDE, MPH

oh wow!! thnks for sharing... 😳

ohooooooooo...i needed dis thnx 😆 😳

thanks for info,as throught this info we can keep control on our caffiene intake quantity as more then enough n excess caffene intake is harmfull.