SUNDAY, May 1 (HealthDay News) -- For middle-aged adults, sleeping less than six or more than eight hours a night is associated with a decline in brain function, British researchers contend. The magnitude of that mental decline is equal to being four to seven years older, the researchers said. “There is an expectation in today’s 24-hour-a-day society that people should be able to fit more into their lives,” said study author Jane Ferrie, a senior research fellow in the department of epidemiology and public health at University College London Medical School.
