Caffeine is the most widely used drug in the world. Coffee, tea, chocolate and many soft drinks contain caffeine, and it is used to flavor some foods. It also is found in medications for staying awake, dieting and treating colds, allergies, migraines and muscle tension.
Caffeine has been a part of the typical daily diet for thousands of years. Americans consume an average of five cups of coffee or an equal amount of caffeine in other drinks and food each day. The amount of caffeine in drinks varies: 6 ounces of brewed coffee has 80-115 mg of caffeine, instant coffee 65 mg, black tea 40-60 mg, cocoa 4 mg, iced tea 35 mg. Caffeine levels in soft drinks vary widely; the average 12-ounce can of cola has 35-60 mg.
What are the effects of caffeine?
Caffeine stimulates the central nervous system. Its effects range from mild alertness to heightened anxiety and body tension. It shortens reaction time among some users. But its impact on creativity and other intellectual activities is hard to define.
Caffeine can be habit-forming. Some regular users who give it up may experience withdrawal symptoms 12-16 hours after the last dose: drowsiness, headaches, lethargy, irritability, disinterest in work, depression, occasional nausea and vomiting.
How caffeine affects you depends on what and how much you drink. Strongly brewed coffee or tea has more caffeine than a weakly brewed drink. Age and body size make a difference, too: A caffeinated soft drink consumed by a child can have the same effect as four cups of coffee for an adult. As with other drugs, how much and how often caffeine is used can affect reactions.
Does caffeine improve performance?
Caffeine may not improve performance of complex tasks; it may even interfere with work. In moderate doses (more than 200 mg, depending on body weight and physical condition) it can produce trembling, nervousness, chronic muscle tension, irritability, throbbing headaches, disorientation, sluggishness, depression and insomnia — otherwise known as “coffee nerves.”
While it may keep you awake for some tasks, caffeine (and other stimulants such as amphetamines or “speed”) will not make up for declining performance caused by lack of rest and exhaustion. You may stay awake for an “all-nighter,” but your memory may be less efficient. In addition, coffee nerves can cause behaviors that may annoy others and add tension to interpersonal interactions.
What if I want to energize?
Morning or afternoon slumps — which affect everyone in some form — are often used as rationale for drinking caffeinated beverages. But there are caffeine-free antidotes to lethargy and dull wits:
- Get a good night’s rest to help stay alert and feel good.
- Try a little exercise — a brisk 10-minute walk around the block or building, for instance — to perk you up.
- Start the day with monotonous, repetitive, boring tasks; save active, demanding tasks for later when they’ll keep you awake.
- Eat regular meals to provide consistent energy intake. These should include a good source of protein such as low-fat dairy products, chicken, turkey or fish. Avoid large meals and foods high in sugar.
- Alcohol intensifies fatigue and sleepiness and slows down your nervous system. Fatty foods also can make you drag.
- Take a brief nap or rest. If your lifestyle won’t permit a breather, some stretches or other physical movement can get you going again.
What are the health risks in using caffeine?
Cigarettes and coffee: Because nicotine raises blood pressure, cigarette smoking increases the risk of cardiovascular complications for anyone with high blood pressure. A typical smoker experiences at least eight hours a day of nicotine-elevated blood pressure. Caffeine can worsen this situation. In addition to blood pressure problems, both increase stomach acid production. Coffee and smoking are a frequent, but unhealthy, combination.
Heart disease and high blood pressure: People with high blood pressure (hypertension) should consult their physician before using caffeine. Limited research links heavy coffee drinking with heart attacks. Caffeine can produce heart rhythm problems, a temporary rise of blood pressure, and those subject to irregular heartbeats should avoid caffeine.
Pregnancy: Caffeine enters the bloodstream and passes through the placental barrier to the fetus. Pregnant women should check with their doctor before taking any drug, including nonprescription medications, many of which contain caffeine. Although no significant link between birth defects and caffeine has been found, mothers-to-be should limit their caffeine intake. Caffeine can be passed to infants in the breast milk of mothers who ingest caffeine. No study indicates its harm, but it may have marked effects on an infant’s behavior, leading to sleep disruptions and irritability.
Anxiety disorders and insomnia: Caffeine acts upon the brain and may affect coordination, sleep patterns and behavior. Delayed sleep, frequent night-time awakenings, poor sleep quality or tension-nervousness cycles may result from excessive caffeine intake.
Itching or pruritis of the skin: Persons with skin problems or dry, scaly skin should note that caffeine may worsen itching and other symptoms.
Other disease links: Researchers continue to explore a possible link between caffeine and cancer. Caffeine may aggravate such existing problems as ulcers, stomach upset and indigestion, and can have a laxative effect. Some studies indicate that caffeine interferes with the kidney’s ability to absorb calcium and increases its excretion: this might put heavy caffeine consumers at greater risk for bone loss.
Although the possibly negative health effects of caffeine are still under study, people with any of these health concerns should reduce their intake.
How can you quit the caffeine habit?
Reduce your intake gradually to avoid tension headaches, coffee nerves and drowsiness. Cut back a cup (or glass) or two a day until the habit is gone. Decaffeinated coffee or other drinks with less or no caffeine are good alternatives. Of course it’s easier not to get into the habit of using caffeine in the morning, at work breaks, or after meals than it is to break those habits. If you pay attention to how you use caffeine, you can better control how it may be using you.
- Keep a log to determine how much caffeine you consume daily. Remember to count nonprescription medications. Then experiment with your caffeine intake and record your feelings and physical reactions.
- Limit your caffeine intake to 2 to 4 cups or glasses daily (less than 200 mg. per day), depending on your own personal tolerance.
- Substitute coffee and teas with herbal teas, hot cider or hot water with lemon.
- Try another activity to give you the same boost — running, walking, swimming, bike riding, yoga, or meditation.
- Eat regular meals to keep your energy level consistent.
- If your coffee drinking is associated with smoking cigarettes, stop smoking. This will break the chain of events and make it easier to cut out coffee.
- Ask the people in your house or office to decrease their caffeine intake along with you.
- Don’t use caffeine while taking antidepressant drugs (it may alter the effectiveness) or high blood pressure medications (it may raise the blood pressure).
- Don’t use caffeine to “sober up” after drinking alcohol. It does not reverse the intoxicating effects of alcohol or affect hangovers.