Energy Drinks Make the Heart Beat Harder: A small study used MRI scans of heart function to show that the heart beats harder up to an hour after consuming energy drinks high in caffeine and taurine. The researchers warned that people with certain medical conditions (arrhythmias in particular) and children should likely avoid such drinks in light of the findings. The researchers said the amount of caffeine in a typical energy drink is about three times higher than the amount found in other caffeinated drinks like coffee. Long-term effects of energy drink consumption are not known, but increased work for the heart’s left ventricle may lead to potentially dangerous arrhythmias, or irregular heart rhythms.