Key ideas from Chris Williamson

• Cortisol awakening response is healthy and necessary - spiking cortisol in the first hour after waking prevents afternoon anxiety and sleep problems
• Make It Stick reveals that learning is repeated recall, not repeated exposure - self-testing beats re-reading for memory retention
• Glymphatic clearance during sleep requires side sleeping with head slightly elevated to wash brain waste through cerebrospinal fluid
• Cold plunge actually reduces cortisol levels despite internet claims - adrenaline and dopamine increase while cortisol decreases
• Atomic Habits demonstrates that understanding mechanism gives flexibility over protocols and allows customization for individual needs
• Burnout typically manifests as either 'wired but tired' or chronically elevated cortisol with disrupted morning-to-evening curve
• Bad habits require top-down prefrontal cortex control, but spiritual practices and higher power concepts provide additional neurobiological support
• Magnesium supplementation protects against hearing loss by maintaining endolymph fluid in the inner ear - next frontier for public acceptance