#136 - Sleep & Sound

Matt returns today to explain why humans didn't evolve for silent sleep. Citing the Hadza and the brain's "open microphone," he explains how we process sound for safety even while resting. He details the "first-night effect," where half the brain stays alert in new environments, demonstrating that our ears never truly switch off.Our host weighs the benefits of noise machines for memory against the risks of dream sleep suppression. He offers evidence-based tips for parents and travelers on using sound effectively, suggesting that earplugs may be better for loud, intermittent noise. He concludes that we should seek "acoustic companionship" rather than total silence to align with our evolutionary design.Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.Hydration impacts cognitive performance and sleep. Pique’s deep hydration protocol features morning B•T Fountain for energy and evening R•E Fountain with Triple Biomaxed Magnesium for nervous system recovery - sugar-free and bioavailable. Get 20% off for life at piquelife.com/mattwalker.Hydrate scientifically with LMNT, a sugar-free electrolyte mix backed by physiology and biochemistry. Try the permanent Lemonade Salt flavor for a balanced, clean boost without the sugar crash. Use Matt’s link to get a free 8-count sample pack with any purchase: drinklmnt.com/mattwalker.Upgrade your oral care with Redmond Life. This fluoride-free, mineral-based toothpaste uses micro-hydroxyapatite to support enamel and bentonite clay for polishing. No harsh chemicals or artificial dyes - just fresh flavors. Use code WALKER for 15% off your first order at redmond.life/walker.As always, if you have thoughts or feedback you’d like to share, please reach out to Matt:Matt: Instagram @drmattwalker, X @sleepdiplomat, YouTube: https://www.youtube.com/channel/UCA3FB1fOtY4Vd8yqLaUvolg