What could cause a healthy 26-year-old to suffer a heart attack? Drinking nearly a dozen energy drinks a day, every day, that's what. A man in Texas told doctors that he regularly consumed eight to 10 caffeine-laden energy drinks a day before suffering a heart attack. He also smoked a pack of cigarettes a day for two years prior to the incident, according to a report published in the journal Case Reports in Emergency Medicine in February 2015. [5 Health Problems Linked to Energy Drinks] It's possible that the excessive amount of caffeine in these drinks, as well as other potentially harmful substances, may have reduced blood flow in the man's coronary blood vessel, causing a blood clot to form and ultimately resulting in a heart attack. The report's authors also noted that smoking may have led to the constriction of the man's coronary artery.