Caffeine reduces myocardial blood flow during exercise

In lecture we learned that caffeine, developed by plants as a natural pesticide, is the most commonly used psychoactive drug in the world, with over 90% of adults in North America consuming it daily.  On average, everyone in the world consumes one caffeinated beverage per day.  The mechanism of action by which caffeine acts is an inhibition of the inhibitory neurotransmitter adenosine.  As the popularity of caffeinated beverages such as energy drinks has increased in the past decade, sudden cardiac death has been reported among teenagers and young athletes who have consumed these products.  This is especially in conjunction with exercising, and this article summarizes the contemporary understanding related to caffeine consumption and reduced exercise coronary blood flow.  It discovered that a dose of caffeine between 200 and 300 mg taken orally at rest has no acute detrimental effect on myocardial blood flow, but when exercising, patients have a significantly reduced coronary vasodilatation.  This could subsequently lead to possible complications including myocardial ischemia, spasm, and arrythmia, especially in those who do not drink caffeine regularly or are exercising at higher altitudes.  In conclusion, the article reads that it is likely that caffeine antagonizes the coronary artery vasodilator effects medicated by the inhibition of adenosine receptors.  Additional research needs to be conducted in order to further understand the underlying mechanisms of caffeine on the body, especially because this is the most widely used psychoactive drug in modern times.  It is also interesting to note that many collegiate students consume caffeine in conjunction with their protein supplements in order to have a more effective workout.  The caffeine component may now be seen as  deleterious to one's potential to gain strength without physiological damage.

Link to article:

http://ac.els-cdn.com.ezaccess.libraries.psu.edu/S0002934313001897/1-s2.0-S0002934313001897-main.pdf?_tid=c8b116d4-dc7f-11e2-a460-00000aab0f01&acdnat=1372045396_fc4690da7ceba9264b5d7f0a8b040e95

http://www.sciencedirect.com.ezaccess.libraries.psu.edu/science/article/pii/S0002934313001897#

http://www.ncbi.nlm.nih.gov.ezaccess.libraries.psu.edu/pubmed/23764265