Overview
- The American Heart Association released a Circulation scientific statement that consolidates trials and large observational studies and recommends about 400 milligrams of caffeine per day as a practical safety threshold for most healthy adults.
- The review found that plain, unsweetened coffee and tea were associated with lower risks of heart disease, stroke, some irregular heart rhythms and type 2 diabetes, with the strongest associations often seen at two to four cups daily.
- The authors explicitly distinguish high‑potency energy drinks from coffee, noting energy products can deliver far higher caffeine doses and have been linked to higher blood pressure and abnormal heart rhythms.
- Researchers emphasized limits of the evidence because most data come from observational studies that show associations but do not prove cause and effect, and they called for more randomized trials to test causality and dose responses.
- The statement stresses that individual factors — genetics, medicines, brewing methods and added sugar or cream — change caffeine’s effects and that clinicians should advise people with heart conditions on personal risks and choices.