Second, sleep too little or even too much. The more significant risk of stroke, heart disease and heart failure. New data reveal that adults who get less than six hours of sleep a night are at significantly greater risk of stroke, heart attack and congestive heart failure. Even those who reportedly sleep more than eight hours a night have a higher prevalence of heart problems, namely chest pain and coronary artery disease, a narrowing of the blood vessels that supply blood and oxygen to the heart