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So I get a lot of questions about caffeine and it is a good topic, because there have been some related injuries and fatalities in the news and it is an ingredient that shows up in more and more food. While this is a legal performance enhancing drug according to USA Track and Field – it is a drug and let’s look at it for a minute in that way.
“DSM-IV lists caffeine intoxication as a clinical syndrome. Caffeine intoxication is described by the following: recent consumption of caffeine and five or more symptoms that develop during, or shortly after, caffeine use including restlessness, nervousness, excitement, insomnia, flushed face, diuresis, and gastrointestinal complaints.” (Medicinenet.com)
The Maryland Poison control center will tell you that at high doses caffeine is a diuretic but also a cardiovascular stimulant, may increase blood pressure, may cause severe nausea and vomiting and cardiac dysrhythmias, (SVT, AF, VT) this dose is considered to be approximately 1000mg or 40mg/kg in a child, a lethal dose is estimated at 150/mg/kg for adults. As an example a 130lb adult would be 59kg. 59x150=8850mg at one time, or at peak effect, and you have to consider that caffeine has a half life of 6 hours in many people. Metabolism of drugs varies by age, body mass, gender, liver and kidney function.
While that sounds like a great amount of caffeine (and it is) that is pretty easy to get in this country today by way of high test beverages and energy drinks. Caution is advised when products do not list the amount of caffeine in the container and supplements or drinks which contain guarana, which is a biological caffeine source in herbal form.
Bear in mind that an average cup of coffee contains 50-180mg of caffeine a cola contains 30-50mg, and a no-doze tablet around 200mg. For a smaller or caffeine –naïve person this could mean that 5-10 no-doze tablets or 10 cups of coffee could be a toxic dose. Some products in concentrate form provide 1800mg in a 4oz bottle and this spells trouble. This dosage information is considering that you are standing still and not running your workout, which is clearly a larger cardiovascular workload and ads up to greater risks for you.
Recall what I have also mentioned about the kidneys and all they do for the body. They can control your blood pressure, to a great degree, using enzymes and hormones that are affected by your hydration status. So let’s say that you are running and sweating, you have increased the cardiac workload and the kidney needs to regulate blood pressure to deal with these two variables. That is a lot of work to do, but if you add caffeine and or NSAIDs (Alleve or Ibuprofen for example) - now you have added a force multiplier to the body’s compensation system and you body may not be able to compensate for these new challenges. This is the type of scenario that has led to fatal injuries of a few runners in the news and injured untold others only slightly less seriously. Know what you are putting into your body, use those powerful substances sparingly, and test the caffeine before race day, using only what you might normally drink in the morning. Consult your doctor and always give them a big picture of what you are doing and what you are taking. Because we think of these items as coming from a grocery store we may falsely assume they are benign and you owe it to yourself to have the best possible race day – so don’t assume anything!
