Too little or too much sleep may take a toll on the heart cardiovascular DISEASE Too little or too much sleep may take a toll on the heart THE QUESTION Daytime drowsiness, difficulty solving problems, lack of creativity and more have been tied to too little sleep. Might heart problems also be attributed, at least in part, to how long people sleep each night? THIS STUDY analyzed data from 15 studies in eight countries, involving 474,684 adults ages 30 and older, whose sleep patterns and cardiovascular health were tracked for up to 25 years. In that time, incidents of heart disease and stroke among the participants totaled 16,067. People who slept, on average, six or fewer hours a night had a 48 percent greater chance of developing or dying from heart disease than did those who averaged seven to eight hours of sleep a night. Among those getting too little sleep, the chance of developing or dying from a stroke was 15 percent higher. In addition, heart disease and stroke were also more common among people who slept longer - nine or more hours nightly. No differences in risk were found between men and women. Adults who chronically sleep more or less than seven to eight hours nightly, the amount considered needed by most adults. Children and teens need more sleep. The idea that older adults need less is generally considered a myth by sleep experts. CAVEATS Data on sleep came from the participants' responses to questionnaires. The authors theorized that longer sleep may have been more of a marker of other health problems linked to heart disease than a cause of such problems. FIND THIS STUDY Feb. 7 online issue of the European Heart Journal (eurheartj.oxfordjournals.org/content/early/recent). LEARN MORE ABOUT healthy sleep at healthysleep.med.harvard.edu and www.nhlbi.nih.gov (search for "healthy sleep").