Caffeine: Are you taking in too much?

  • Published
  • By Bill Goins
  • 8th Fighter Wing Exercise Physiologist
How many mornings do you start-off by reaching for a cup of coffee, a Red Bull, or some other energy drink...or two, or three? How about throughout the day? Most people are unaware of how much caffeine they are really taking in. Current data suggests that the average American consumes approximately 200 milligrams of caffeine daily, or about 2 cups of coffee. The same research also shows that about 10 percent of the population consumes more than 1000 milligrams per day through coffee, tea, soft drinks, energy drinks and dietary supplements.

There is plenty of research out there that shows caffeine intake, in certain amounts, can be beneficial to exercise performance. However, as with so many other things, we figure if some is good...more must be better. I recently overheard an individual talking about drinking two large energy drinks and taking caffeinated supplements before his fitness assessment because he figured it would improve his performance. More is better...right? I'll come back to him later.

Caffeine is a central nervous system stimulant, which means it makes you feel more awake, energized and aware of your surroundings. It is absorbed by the body fairly quickly and can affect all of your body's systems. In well-trained elite athletes, laboratory research has shown caffeine ingestion, of approximately 3 milligrams/kilogram of body weight one hour prior to exercise, can increase performance during prolonged endurance exercise and short-term intense exercise lasting 5 minutes. The mechanisms for improved endurance have not been clearly established. Muscle glycogen sparing (the body's use of non-carbohydrates as a source of energy during exercise, like fat) occurs early during endurance exercises following caffeine ingestion. However, it is unclear if this is due to increased fat mobilization and use by the muscle, or as a result of some other combination of physiological effects.

To put this in to perspective, a 175 pound athlete who consumes 3 milligrams of caffeine per kilogram of body weight could consume around 235 milligrams of caffeine and could see some benefits. An 8 ounce cup of generic brewed coffee has between 100-200 milligrams of caffeine. The potential downside is if this particular athlete does not generally consume caffeine as the effects of the caffeine could not be tolerated well by the individual. Another possible downside could be if the individual already consumed caffeine earlier that same day. The potential negative effects of caffeine over-consumption are well documented and include high sustained heart rate, anxiety/depression, restlessness, tremors, and sleep deprivation, and many more. So I think it is important to realize that additional field studies need to be conducted to translate the results of studies showing potential benefits in the real world and with every day athletes like you and me.

So how much caffeine is considered "safe". The National Institutes for Health say that 250 milligrams of caffeine daily should be relatively safe for most individuals. So how many milligrams of caffeine are in some of the most commonly consumed caffeinated products?

1 cup (8 ounces) of generic brewed coffee = 100-200 mg
1 cup of brewed black tea = 15-60 mg
12-ounce soft drink = 30-55 mg
1 cup of green tea = 25-40 mg
1 severing size shot (2 ounces) of 5-Hour Energy = 207 mg
8.4-ounce Red Bull energy drink = 76 mg
8-ounce Monster energy drink = 80 mg
8-ounce Rockstar energy drink = 80 mg

This brings me back to the individual I overheard talking about the two large energy drinks and the four capsules of a popular energy supplement he took right before an FA. He could not understand why he felt so jittery. This individual consumed approximately 600-650 milligrams of caffeine less than 30 minutes before his test. Definitely not recommended!

Bottom line: In low doses, caffeine can provide certain benefits, but it can have serious side effects if consumed in larger amounts. Enjoy your coffee ... but I would not recommend large doses of caffeine before you exercise or test. Not only does the research not support benefits when consumed in those large amounts, but it also has been conducted largely in controlled settings and on extremely fit, elite athletes. If you are considering increasing your caffeine intake, please consult your provider or contact us at the Health and Wellness Center for further assistance at 782-4305.