Too little sleep may speed up aging. Not surprising, but researchers at Columbia University Irving Medical Center report too much sleep may also age our brain faster. This study used aging clocks—massive amounts of data and machine learning. Multiple aging clocks were applied to multiple organ systems to learn how sleep affects each of the systems. Researchers confirmed that sleeping fewer than six hours a night or greater than eight hours were associated with faster biological aging than people who averaged between six and a half and seven point eight hours. They caution that sleep duration alone does not cause organs to age faster or slower, but the findings suggest too little or too much sleep may be markers of poorer overall health.