American Heart Association says up to 400 mg caffeine daily safe for most adults

The American Heart Association (AHA) released a scientific statement in the journal Circulation recommending that most adults can safely consume up to 400 mg of caffeine per day – roughly five 8‑oz cups of black coffee – without increasing cardiovascular risk.

The analysis linked this level of intake to lower odds of heart failure, coronary disease, stroke, hypertension and type‑2 diabetes, especially when coffee is consumed without added sugars or cream. It warned that high‑dose caffeine sources such as energy drinks may raise heart‑related risks. Benefits vary by individual metabolism and genetics, and the lowest mortality risk was observed at two to four cups per day.