Caffeine as a Cardioprotective and Cardiotoxic Agent: A Review of Recent Evidence

Caffeine is the most widely consumed psychoactive substance worldwide and is ingested daily in coffee, tea, cocoa, energy drinks, and dietary supplements. Its cardiovascular effects remain controversial because both beneficial and harmful associations have been reported. This review synthesizes recent evidence on the cardioprotective and cardiotoxic effects of caffeine, with particular attention to dose-response relationships, habitual versus acute exposure, product type, arrhythmias, blood pressure, heart failure, endothelial function, and genetic variability in caffeine metabolism. Available evidence from large cohort studies and reviews indicates that moderate habitual intake, particularly from traditional coffee consumption, is generally associated with a favorable cardiovascular profile, including lower cardiovascular and all-cause mortality and a lower risk of incident heart failure in some populations (Chieng et al., 2022; Poole et al., 2017; Stevens et al., 2021). Moderate intake does not appear to increase atrial fibrillation risk in the general population and may be neutral or modestly favorable in observational studies (Caldeira et al., 2013; Cheng et al., 2014; Surma et al., 2023). In contrast, acute high-dose exposure, especially from energy drinks and concentrated stimulant products, may increase blood pressure, provoke sympathetic overstimulation, and contribute to electrocardiographic changes such as QTc prolongation in susceptible individuals (Mandato et al., 2025; Voskoboinik et al., 2019). These effects are modified by individual metabolic variability, especially CYP1A2-related differences, lifestyle factors, baseline tolerance, and co-exposures (Cornelis et al., 2006; Palatini et al., 2009). Overall, the cardiovascular effects of caffeine are best understood as dose dependent, context dependent, and biologically heterogeneous. Moderate intake appears generally safe for most healthy adults, whereas high-dose products warrant greater caution and more personalized guidance.