Any avid coffee drinker can tell you that a little caffeine can get your heart rate pumping a little faster...for some obvious and some not so obvious reasons. Caffeine is a stimulant, and like most "uppers," it gets your body--including your heart--moving at quicker, sometimes more efficient rates.
Caffeine is the most widely used stimulant in the world, and is found naturally in coffee beans and tea leaves. Caffeine can be consumed in many other ways as well: energy drinks, tea, yerba mate, in pill form, sodas, and even some foods like chocolate. Studies even suggest that 80% of American adults consume caffeine on a daily basis!
As for heart rate, caffeine is a central nervous system stimulant. It is in a class with other psychoactive drugs like epinephrine, amphetamines, cocaine, Ecstacy, nicotine and other ADHD medications like Ritalin. It is one of the few psychoactives that is legal.
Does Caffeine Really Raise Heart Rate?
YES...Studies show that caffeine consumption raises blood pressure, or stroke volume of the heart by 4 points per minute, and heart rate goes up by about 3 beats per minute. Caffeine consumption raises pulse rates by stimulating cardiac cells. Some studies claim that caffeine doesn't have an effect on heart rates, however, people do build a tolerance to caffeine, therefore, you may not feel the effects if you regularly drink a few cups every day.
Caffeine is also known to increase metabolism, so many people who are attempting to lose weight may begin to drink coffee, green tea, or take caffeine pills as part of a diet and work out plan. This metabolic boost happens thanks to an increase in heart rate that can last for a few hours after consumption. It does not, however, raise heart rate enough to be a substitiute for a workout! It is also somewhat counteracted if you are adding flavoring, milk or sugar to your beverage, so keep those calories in check!
Althletes know that caffeine consumption increases speed and performance because of increased cellular activity. Caffeine has been shown to increase dopamine in the pleasure center of the brain, to increase performance times in exercisers and athletes, motivating them to have a more effective sweat session. This happens mostly due to decreased fatigue symptoms, but does NOT increase the ability to lift more weight. In many international events, caffeine is often restricted to the amount in a cup or two of coffee.
How Caffeine Affects the Body
Caffeine stimulates heart rate through a well documented process in the cardiac cells. Caffeine blocks the enzyme phosphodiesterace, which normally actviates production of an enzyme, cyclic AMP (cAMP), which initates a protein that increases heart rate. There are usually checks and balances here, and heart rate is regulated as cAMP is kept in check in a drug free cell. When caffeine is introduced, that cAMP check is eliminated, putting the protein (PKA) in overdrive. Therefore, heart rate is increased when caffeine is consumed.
Caffeine elevates heart rate, having a positive effect on exercisers and people who are trying to lose weight. It's important to consider the negative effects of caffeine consumption--especially overconsumption--on on the body before you make it your go-to beverage of choice.