Poor sleep in middle age could affect the brain in a surprising way, study finds

There are some obvious signs of a poor night's sleep -- fatigue, irritability and trouble focusing, to name a few -- but it can also have some hidden effects. In a new study led by University of California, San Francisco (UCSF), poor sleep was linked to faster brain aging in middle-aged adults. While previous studies have focused on older adults, the average age of the 589 people in this study was 40 years old, according to a press release. The participants completed two sleep questionnaires five years apart. After 15 years, they underwent brain scans.