1. THE NUMBERS DON’T LIE. Caffeine is a naturally occurring mild chemical stimulant that exists in a variety of foodstuff, including coffee, tea, chocolate, and cola drinks. Without question, the average individual consumes a copious amount of caffeine annually. Just in the United States, for example, more than a million metric tons of coffee and three billion pounds of chocolate are ingested each year. As such, caffeine in one form or another is America’s most popular drug by far.
2. CAFFEINE BUZZ. To a degree, the perceived "jolt" that many people experience when they drink a cup of coffee is real. Caffeine stimulates your central nervous system by blocking the neurotransmitter (adenosine) that usually causes a calming effect in the body. As a consequence of the subsequent changes in brain chemistry that occur, you experience an increase in neuron firing, the nerve cells speed up, and the blood vessels in the brain constrict. Your pituitary gland then responds by releasing hormones that tell your adrenal glands to produce adrenaline. Bingo! You feel more alert.
3. PACE YOURSELF. For many people, caffeine is the drug of choice. As such, statistics indicate that in the United States, approximately 75% of the caffeine intake of the average American comes from coffee. Like most things in life, however, a point can be reached where consuming too much coffee (e.g., more than three cups a day) can lead to some relatively unpleasant side effects, including irritability, upset stomach, fast heartbeat, insomnia, and so on.
4. PERFORMANCE ENHANCER. A number of studies have documented the positive effect that caffeine can have on athletic endurance performance. As a result, both the International Olympic Committee and the National Collegiate Athletic Association have placed an upper limit on the amount of caffeine that is permissible in an athlete’s urine after competition (a level equal to roughly four to seven cups of coffee). On the other hand, caffeine has not been found to elicit improvement in activities involving exerting manual musculature force.
5. DRAINING THE WELL. Contrary to opinion of many people, consuming caffeinated beverages doesn’t actually cause dehydration, although it does act as a mild diuretic. Although caffeine may increase your urge to urinate, whatever caffeinated fluid you drink tends to offset the fluid that is lost through urination.
6. A SOBERING MYTH. People only think that caffeine sobers them up after an extended bout of alcohol consumption. Truth be known, to a limited point, caffeine may enhance the level of alertness of an individual who has been drinking; however, that person’s reaction time and judgment are still diminished. Sobriety has not been achieved.
7. THE HEROIN/COCAINE CONNECTION. Similar to both heroin and cocaine, caffeine slows down the body’s rate of reabsorbing dopamine - a neurotransmitter that activates pleasure centers in various areas of the brain. Although the effect of caffeine is much weaker than either of the two hard drugs, the physiological mechanism for increasing the body’s level of dopamine is pretty much the same.
8. "POTENTIAL" IS A NINE-LETTER WORD. Although caffeine has few proven health benefits, the list of caffeine’s potential medical benefits is somewhat compelling. For example, studies have found that regular coffee drinkers can reduce their risk of Parkinson’s disease by almost 80%. In turn, drinking two cups of coffee a day can lower a person’s risk for colon cancer and gallstones by 20% and 50%, respectively.
9. ALL IS NOT ROSY. Although the consumption of caffeine, when ingested in an appropriate amount, seems to be safe for most adults, some medically related downsides to caffeine can exist. For example, in some instances, caffeine can worsen anxiety disorders and bipolar disorders. Caffeine also can aggravate bleeding disorders and cause the heart to beat irregularly. In addition, caffeine can worsen the effects of diabetes and can increase the pressure inside the eye - a particularly negative factor for individuals with glaucoma. Collectively, the situation suggests that caution should be used when consuming more than a moderate level of caffeine on a daily basis.
10. A PATHWAY TO REASON. Although caffeine can be addictive in some people, a person’s consumption of caffeine can be reduced, provided that the individual undertakes targeted steps to address his or her caffeine habit. For example, keeping a log to see how much caffeine is actually consumed is a good starting point. The next step should be to gradually reduce the amount of daily caffeine consumption. Another potentially worthwhile action would be to identify and ingest an appropriate substitute foodstuff, for example, decaffeinated coffee.
James A. Peterson, Ph.D., FACSM, is a freelance writer and consultant in sports medicine. From 1990 until 1995, Dr. Peterson was director of sports medicine with StairMaster. Until that time, he was professor of physical education at the United States Military Academy.
Copyright 2010 by the American College of Sports Medicine.