If you notice your heartbeat quicken after drinking a can of cola, it may not be your imagination. Some soft drinks contain caffeine, which is a natural stimulant that can affect your heart rate. If this happens each time you drink soda, consider switching to a variety labeled caffeine-free -- or better yet, drink water instead. Rapid heart rate can also indicate a medical condition, so see your doctor if symptoms persist or are severe.
The Caffeine Effect
Caffeine can elevate your heart and breathing rates, and temporarily boost your energy. In a study published in the "Journal of Food Science" in 2007, brand-name colas and diet colas tested at 34 to 46 milligrams of caffeine per 12 ounces, while other soda varieties contained as much as 55 milligrams in the same serving. Store brands generally had less caffeine. Drinking 250 milligrams of caffeine daily is considered moderate intake. However, some people are sensitive to even a small amount of caffeine.