Sleeping on your side — as opposed to your back or tummy — appears to more effectively remove brain waste and so could help reduce your chances of developing Alzheimer’s, Parkinson’s and other neurological diseases, according to researchers at Stony Brook University. While we sleep, our brains are actively in clean-up mode, sweeping up the junk and gunk that accumulate while we are awake. In the Stony Brook study, researchers Helene Benveniste and Hedok Lee used dynamic contrast magnetic resonance imaging (MRI) to image the glymphatic pathway in the brains of rodents. The glymphatic pathway is a complex system that clears wastes and other harmful chemical solutes from the brain. And what they found is that sleeping on the side is the best position to most efficiently remove waste from the brain. Fun fact: Side sleeping, also called lateral sleeping, is the most common sleep position for both humans and animals, including animals in the wild. We may have evolved this way simply because it is the best position for the brain.