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Health & Exercise Forum

The Truth About Caffeine: Part 1 of 2

Aug 11, 2014

Dr. Mackarey's Health & Exercise ForumMost of us are all too familiar with someone in our family or workplace that can be described as a hyperactive or high energy person. I am sure members of my family or coworkers in my office are thinking that this statement is a self-description. Consequently, based on doctor’s advice, it is best to limit me to one cup of coffee or pay the price when I become a hyperactive taskmaster. Now, after further research on this topic, I have concluded that it may be that I am just be hyperactive by nature, regardless of my caffeine intake. While many of you may find the following facts hard to believe, and the effects of caffeine may vary for each individual, the facts are still the facts.


Approximately 80% of the world's population consumes caffeine on a daily basis. While research is constantly being done on health benefits and side-effects of caffeine, great controversy and misconception persists. The purpose of this column will be to discuss the “current wisdom” and present the truth about caffeine.

Caffeine is completely absorbed within 30 to 45 minutes of ingestion and its effects linger for about three hours. Eventually it is excreted and there is no accumulation in the body. Caffeine has been shown to affect mood, stamina, the blood vessels in the brain, as well as stomach and intestinal activity. However, for most people, when used in moderation (200 to 300mg or 2-3 cups), caffeine use is perfectly safe and may offer some health benefits.

Sources of Caffeine

Caffeine is a natural substance found in certain leaves, seeds, and fruits of over 60 plants worldwide. In our culture, the most common sources in our diet are coffee, tea leaves, cocoa beans, cola, and energy drinks. Caffeine can also be produced synthetically and added to food, beverages, supplements, and medications. Consumption of 130 to 300 mg of caffeine per day is considered minimal to moderate. Amounts exceeding 500 mg are moderate to heavy and more than 1000 mg/day is excessive. The average daily caffeine consumption among Americans is about 280 mg/day and 20% to 30% consume more than 600 mg/day. Caffeine contents in some of the more popular forms are:

  • 8 oz. brewed coffee = 133 mg caffeine
  • 8 oz. decaffeinated coffee = 5 mg caffeine
  • 2 oz. Starbucks double espresso = 150 mg caffeine
  • 12 oz. Diet Coke = 47 mg caffeine
  • 8.3 oz Red Bull = 80 mg caffeine
  • 8 oz hot cocoa = 9 mg caffeine
  • 12 oz Jolt Cola = 72 mg caffeine
  • 8 oz black tea = 53 mg caffeine

NEXT MONDAY – Read Dr. Paul J. Mackarey “Health & Exercise Forum”  in the Scranton Times-Tribune: Common Misconceptions About Caffeine.

Paul J. Mackarey PT, DHSc, OCS is a Doctor in Health Sciences specializing in orthopaedic and sports physical therapy. Dr. Mackarey is in private practice and is an associate professor of clinical medicine at The Commonwealth Medical College.