Kevin J. Tracey, MD is president and CEO of the Feinstein Institutes for Medical Research at Northwell Health, a pioneer of vagus nerve research and author of the recent book, The Great Nerve: The New Science of the Vagus Nerve and How to Harness Its Healing Reflexes. This episode is brought to you by: Eight Sleep Pod Cover 5 sleeping solution for dynamic cooling and heating: EightSleep.com/Tim (use code TIM to get $350 off your very own Pod 5 Ultra.) AG1 all-in-one nutritional supplement: https://DrinkAG1.com/Tim (1-year supply of Vitamin D plus 5 free AG1 travel packs with your first subscription purchase.) Wealthfront high-yield cash account: https://Wealthfront.com/Tim (Start earning 4.00% APY on your short-term cash until you’re ready to invest. And when new clients open an account today, you can get an extra fifty-dollar bonus with a deposit of five hundred dollars or more.) Terms apply. Tim Ferriss receives cash compensation from Wealthfront Brokerage, LLC for advertising and holds a non-controlling equity interest in the corporate parent of Wealthfront Brokerage. See full disclosures here. Tim Ferriss is one of Fast Company’s “Most Innovative Business People” and an early-stage tech investor/advisor in Uber, Facebook, Twitter, Shopify, Duolingo, Alibaba, and 50+ other companies. He is also the author of five #1 New York Times and Wall Street Journal bestsellers: The 4-Hour Workweek, The 4-Hour Body, The 4-Hour Chef, Tools of Titans and Tribe of Mentors. The Observer and other media have named him “the Oprah of audio” due to the influence of his podcast, The Tim Ferriss Show, which has exceeded 900 million downloads and been selected for “Best of Apple Podcasts” three years running. Sign up for "5-Bullet Friday" (Tim's free weekly email newsletter): https://go.tim.blog/5-bullet-friday-yt/ Follow the Tim Ferriss Podcast: https://tim.blog/podcast/ Visit the Tim Ferriss Blog: https://tim.blog/ Follow Tim Ferriss on Twitter: https://twitter.com/tferriss/ Follow Tim Ferriss on Instagram: https://www.instagram.com/timferriss/ Corrections: 02:09:25 Dr. Tracey meant "Liz Blackburn."