In fact, several large recent studies report that regular caffeine intake is associated with a 8-39% reduction in death from any cause, including cardiovascular disease. Most studies have not found a link between caffeine consumption and negative cardiovascular outcomes, such as high blood pressure or risk of heart disease. whether you are a fast, intermediate, or slow metaboliser. Of course, the exact acute and chronic cardiovascular effects of caffeine depend on various factors, such as the dose of caffeine and how it’s consumed, as well as individual variables, such as whether or not someone is a regular caffeine consumer and how quickly they break down caffeine based on their genetics.Īs we’ll explore in later sections, there is some evidence that the chronic caffeine intake has differing cardiovascular effects depending on how fast you break down caffeine i.e. The underlying mechanisms behind this association are not clear, but may be partly due to the fact that long term caffeine consumption can enhance production of nitric oxide, a molecule that dilates blood vessels. With this caveat in mind, some studies have shown that habitual caffeine consumption is associated with a reduced risk of cardiovascular disease such as heart failure, coronary artery disease, and heart failure. The drawback of this method is that we cannot be certain whether it is caffeine per se, or another nutrient within coffee,tea, etc.,that is responsible for any long-term cardiovascular effects. blood pressure, incidence of heart attack) and consumption of caffeinated-drinks such as tea and coffee. Studies of the longer term effects of caffeine consumption have been largely based on observational studies investigating the relationship between various cardiovascular health parameters (e.g. These doses are extremely high, however, and most evidence suggests that typical caffeine intake is not associated with an increased risk of arrhythmia. In extremely high doses, caffeine may cause an irregular heartbeat (known as arrhythmia) and also reduce blood flow to the heart. By breaking down caffeine more quickly, habitual caffeine consumers experience less pronounced acute cardiovascular effects of a given caffeine dose. One of these adaptations to regular caffeine consumption is an increase in the activity of CYP1A2, the enzyme which breaks down caffeine. Importantly, however, the same meta-analysis found that our bodies adapt to habitual caffeine consumption and that acute rises in blood pressure were not present after 2 weeks. Trends in cardiovascular medicine, 29(6), 345-350. Cardiovascular effects of caffeinated beverages. Source:Voskoboinik, A., Koh, Y., & Kistler, P. This rise in blood pressure was observed in the first 1-3 hours after consuming caffeine. On this note, a 2011 meta-analysis of controlled trials in people with hypertension (high blood pressure) found that a 200-300 mg dose of caffeine (equivalent to about 2-3 8oz cups of coffee) led to a 5.7 and 8.1 mm Hg rise in diastolic and systolic blood pressure, respectively. The combination of vasoconstriction and increased effects may cause a small, transient rise in blood pressure after ingesting caffeine. Similarly, caffeine also inhibits the adenosine receptor and a cellular enzyme called phosphodiesterase, which leads to vasoconstriction and increases in heart rate. Two key hormones involved in the fight-or-flight response are adrenaline and noradrenaline, and caffeine is shown to elevate circulating levels of these hormones, thereby stimulating our sympathetic nervous system. These effects occur because caffeine is a sympathomimetic, meaning it stimulates our sympathetic nervous system (which is responsible for our body’s fight-or-flight response). In the first hour after drinking a cup of coffee, our heart rate increases and our blood vessels (including the coronary arteries supplying the heart) temporarily become narrower (known as vasoconstriction). When discussing the effects of caffeine, it is important to distinguish between those effects that are short-term or acute, and manifest shortly (minutes to hours) after drinking a cup of coffee, from those that are long-term or chronic, which occur when someone habitually drinks coffee over longer periods (years to decades). What are the effects of caffeine on the cardiovascular system?
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