Sleeping is the body’s primary way to rest and recharge, and that translates to the brain, as well. “Sleep is conducive to detoxification of the brain,” Brownlow explains, and our glymphatic system—the waste clearance mechanism for the brain—can kick into high gear as we rest.
In this way, sleep has a neuroprotective purpose, and it can protect us from some of the cognitive health changes often seen in older age. One 2015 study notes that sleep has been linked with improved memory recall and reduced mental fatigue, among other things. “When one sleeps, the brain reorganizes and recharges itself and removes toxic waste byproducts, which have accumulated throughout the day. This evidence demonstrates that sleeping can clear the brain and help maintain its normal functioning,” the study authors write.
However, this study also indicates that a minimum of seven hours of sleep every night “seems to be necessary for proper cognitive and behavioral function.” As mbg vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN, noted in the podcast with Brownlow, over one-third of American adults aren’t meeting this threshold.