Are you sitting right now? If you want to protect your brain, you should take a walk and be sure to go to bed early. Regular exercise and about seven hours of sleep a night could protect brain health in the long term, a study published Wednesday in the journal PLOS One found. Long bouts of sedentary behavior may increase dementia risk. It’s the latest data to show that people don’t need elaborate and expensive longevity hacks to stay mentally sharp as they age. Simple lifestyle changes could