Caffeine: Too Much of a Good Thing?

Let’s face it, for many of us, our day is not complete without a jolt of java. Research has revealed that upwards of 85 percent of Americans drink a cup of coffee every day[i]. And for many of us, our daily coffee consumption is not limited to just one cup.

But how much caffeine is too much? The FDA states that about 400 milligrams per day is safe for healthy adults. That equates to about four to five cups of coffee.

Remember, however, that caffeine is not only found in coffee. It can be found in colas, tea and energy drinks. A 12-ounce can of a caffeinated soft drink typically contains 30 to 40 milligrams of caffeine. An 8-ounce cup of green or black tea is about 30 to 50 milligrams, and an eight-ounce cup of coffee is closer to 80 to 100 milligrams. But the caffeine in energy drinks can range from 40 to 250 milligrams per eight fluid ounces!

Over-consumption of caffeine can cause:

  • insomnia
  • jitters
  • anxiousness
  • fast heart rate
  • upset stomach
  • nausea
  • headache
  • a feeling of unhappiness 


It is important to remember that peoples caffeine sensitivity can vary widely in their and how quickly their bodies’ metabolize it. Some people can drink several cups of coffee without experiencing any negative side effects while for others, one cup might lead to a rapid heart rate. 

Energy drinks, in particular, should be approached with caution, especially among young adults and teens. Sales of these beverages have skyrocketed, with 18-to 38-year-olds being the highest consumers of these products. But studies have indicated that these drinks may be linked to heart problems in young people, including heart attacks and atrial fibrillation.[ii] Although there is no conclusive evidence that these conditions can occur due to high caffeine levels or other ingredients in these drinks (or a combination of both), there is evidence that high doses of caffeine alone can be toxic.[iii]

If you want to cut back on caffeine, it is best to do so gradually. If you quit abruptly, you may suffer from headaches and anxiety. Talk to your Virginia Heart specialists about the best way to decrease—or end—your caffeine consumption. 

Virginia Heart is Northern Virginia’s premier cardiovascular group, with more than 40 board certified Cardiovascular Specialists who provide expertise in treating a wide range of conditions that affect the body's heart and vascular systems.