The perks and pitfalls of caffeine

Extra-large coffee, black! Grande vanilla latte! Double cappuccino! Cup of tea with two bags! Sound familiar? You might count on caffeine to keep you alert and get you through the day – but have you ever thought about the other ways caffeine might affect you?

Caffeine is a natural stimulant found in many foods including coffee, tea, some soft drinks, and chocolate. Some cold medicines and pain relievers have caffeine in them, too. Caffeine is actually the most widely-used “drug” in America. About 80% of the US population uses some form of it daily. The average American takes in about 200 milligrams of caffeine each day (about as much as in two 5-ounce cups of coffee).

How does caffeine work?

Caffeine affects your central nervous system (your brain, specifically); it gets in the way of a chemical in your body called adenosine (pronounced ah-den-oh-seen). Adenosine slows down your brain activity and helps you fall asleep. As the caffeine blocks the effects of adenosine, you feel more awake and alert. You’ll usually start to feel the effects of caffeine within 15 minutes to an hour, but it can stay in your bloodstream and have lasting effects for four to six hours.

Is caffeine healthy or harmful?

Moderate caffeine use (two 5-ounce cups of coffee each day, for example) isn’t usually considered harmful for most healthy adults. Caffeine is sometimes helpful and actually a key ingredient in some over-the-counter and prescription pain medications; for example, caffeine can be found in some medicines that treat migraine headaches. Migraine headache pain sometimes occurs when the blood vessels in the brain become swollen and inflamed. Caffeine can sometimes help these blood vessels shrink back to a more normal size and relieve some of the pain. Some research also suggests that caffeine can boost the effects of certain medications, or help the body absorb them faster.

Too much caffeine (five 5-ounce cups of coffee or more each day) may cause some bad side effects, such as:

  • High blood pressure
  • Fast heartbeat
  • Shakiness
  • Anxiety
  • Irritability
  • Trouble sleeping
  • Stomach upset
  • Frequent urination—going to the bathroom often
  • Dehydration—feeling thirsty, confused, or dizzy

How can you cut back?

If you have caffeine every day, your body can get used to it and may start to depend on it. Cutting out caffeine all at once can actually cause you to get a headache; it may also make you feel tired, anxious, or depressed. If you’re looking to use less caffeine, it’s usually better to cut back a little bit at a time. For example, try drinking your coffee or tea from a smaller cup. If you think caffeine is making it hard for you to sleep, try avoiding it, or switch to decaf after lunch time. Most importantly, speak with your doctor or healthcare provider if you think you might be having any caffeine-related side effects.

The bottom line? If a cup of “Joe,” tea, or cola is part of your everyday routine, continue to enjoy it – but pay attention to how much caffeine you’re using and how it’s affecting you. It is also important to understand that sometimes caffeine may need to be avoided, which is a discussion for you to have with your health care provider.


For more information, check out this article from the National Institutes of Health.


Attwood, A. S., Higgs, S., & Terry, P. (2007). Differential responsiveness to caffeine and perceived effects of caffeine in moderate and high regular caffeine consumers. Psychopharmacology, 190, 469-477.

Maridakis, V., O’Connor, P. J., Dudley, G. A., & McCully, K. K. (2007). Caffeine attenuates delayed-onset muscle pain and force loss following eccentric exercise. Journal of Pain, 8(3), 237-243.

Mayo Clinic. (2011). Caffeine: How much is too much? Retrieved from

Shapiro, R. E., & Cowan, R. (2011). Caffeine and migraine. Retrieved from the American Headache Society website:

Shapiro, R. E. (2007). Caffeine and headaches. Neurological Sciences, 28, Supplement 2, S179-S183. Retrieved from:

U.S. Food and Drug Administration. (2007). Caffeine and your body. Retrieved from