From the Guidelines
Caffeine does not decrease heart rate, but rather, it can increase heart rate and exacerbate arrhythmias. According to the study by the American Heart Association 1, recent ingestion of caffeine may exacerbate arrhythmias, particularly during exercise. The study highlights that exercise-induced arrhythmias are generated by enhanced sympathetic tone, increased myocardial oxygen demand, or both, and caffeine can further contribute to this effect.
Key Points to Consider
- Caffeine is a stimulant that can increase heart rate and blood pressure
- Exercise-induced arrhythmias can be exacerbated by caffeine consumption
- The American Heart Association study 1 suggests that caffeine can contribute to enhanced sympathetic tone and increased myocardial oxygen demand, leading to arrhythmias
- Individuals with heart conditions or those sensitive to caffeine may experience more pronounced effects, including palpitations or irregular heartbeats
Clinical Implications
- Patients with pre-existing heart conditions should be cautious when consuming caffeine
- Caffeine intake should be limited, especially in individuals who experience arrhythmias or other cardiac symptoms
- Healthcare providers should consider the potential effects of caffeine on heart rate and arrhythmias when advising patients on caffeine consumption.
From the FDA Drug Label
Although no cases of cardiac toxicity were reported in the placebo-controlled trial, caffeine has been shown to increase heart rate, left ventricular output, and stroke volume in published studies.
Caffeine does not decrease heart rate, it increases heart rate, left ventricular output, and stroke volume in published studies 2.
From the Research
Caffeine's Effect on Heart Rate
- The study 3 found no difference in heart rates in participants after 30-90 min of drinking either caffeinated or decaffeinated coffee.
- Research 4 suggests that caffeine produces acute rises in systolic and diastolic blood pressure, but heart rate data are less consistent.
- A review 5 reports that for healthy adults, caffeine consumption is relatively safe, but for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function.
- The evaluation 6 of the scientific literature on caffeine found that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect on heart rate.
- A recent review 7 summarizes the mechanisms of coffee action on the heart muscle and the results of clinical trials assessing the impact of coffee consumption on the risk of various cardiac arrhythmias, but does not specifically address the effect of caffeine on heart rate.
Key Findings
- Most studies suggest that moderate caffeine intake does not have a significant impact on heart rate in healthy adults.
- However, individual responses to caffeine may vary, and some people may experience changes in heart rate after consuming caffeine.
- More research is needed to fully understand the effects of caffeine on heart rate, particularly in vulnerable populations.