Most people think longevity is about diet and supplements. Alexis Fernandez, cognitive neuroscientist, says the real killers are chronic stress, isolation, and outsourcing your brain to your phone. In this episode of Project 100, Mark Bouris sits down with Alexis to unpack what the science on centenarians actually shows — and it's simpler, and more confronting, than most people want to hear. From cortisol dysregulation to synaptic pruning to why resistance training is the best thing you can do for your brain, this conversation will change how you think about what it means to age well.