Mega Monster, Red Bull, Vamp, Octane, Coke, even coffee or tea. People often ingest caffeinated beverages prior to an intense workout for a harmless energy boost. Is it really harmless though?
According to a 2006 study conducted by the Journal of the American College of Cardiology (JACC), the amount of caffeine in just two cups of coffee limits the body's ability to increase blood flow to the heart during exercise. This raises a red flag because blood flow to the heart must increase during exercise in order to meet the body's higher demand for oxygen and nutrients. Furthermore, according to the article, athletes who ingest caffeine before performing may feel that they are enhancing performance, but these researchers suggest that the athletes are simply more alert, awake and focused.
On the other hand, other studies conducted have found that moderate amounts of caffeine are harmless and do indeed enhance performance in both endurance-type activities and short, power-intensive activities. According to Fitday.com, caffeine delays the onset of muscle fatigue by helping your body use its own fat reserves as energy instead. This reduces the glycogen burn rate, known as "glycogen sparing." The longer your glycogen lasts, the longer your muscles can function.
Another study conducted by the Australian Institute of Sport had similar findings: that caffeine triggers the muscles to start using fat as an energy source instead of carbohydrate sugars. Studies on elite distance runners and swimmers showed an increase in their performance times after they had ingested caffeine.
To sum it up, there seems to be no definitive answer as to whether or not it is safe to ingest caffeine prior to exercising. Lots of intricate studies have been conducted with varying outcomes and conclusions. Since different studies show different results, it may be best to research and look into the experts' opinions more thoroughly and draw your own conclusion based on credible and reliable sources.
NOTE: Make sure you get medical clearance before trying any new exercise or activity, and/or if you are starting a new workout regimen. If you feel abnormal pain or discomfort, stop and contact your health care provider. Do not ingest an excessive amount of caffeine unless a physician authorizes it.