In this episode, I interview Dr. Robert Sapolsky, Ph.D., Professor of Biology, Neurology & Neurosurgery at Stanford University. We discuss stress, what defines short-term versus long-term stress, and how stress can be beneficial or detrimental, depending on the context. We also discuss stress mitigation and how our sense of control over stress mitigation techniques, including exercise, determine health outcomes. Dr. Sapolsky explains some of the key effects of the hormone testosterone — how it can amplify pre-existing tendencies for aggression or sexual behavior, but that it does not produce those behaviors per se. He also explains how testosterone impacts our social hierarchies, sense of confidence, and willingness to embrace challenges of different kinds. He also explains how our behaviors and perceptions shape testosterone levels. And we discuss estrogen and the powerful role it plays in brain development, health and longevity. Finally, we discuss free will, what it means to have free will, and if we have any free will, including how knowledge alone might allow us to make better decisions for ourselves and society.    Thank you to our sponsors: ROKA - https://roka.com - use code "huberman" InsideTracker - https://insidetracker.com/huberman  Belcampo - https://belcampo.com/huberman    Our Patreon page: https://www.patreon.com/andrewhuberman    Supplements from Thorne: http://www.thorne.com/u/huberman    Social: Instagram - https://www.instagram.com/hubermanlab  Twitter - https://twitter.com/hubermanlab  Facebook - https://www.facebook.com/hubermanlab   Website - https://hubermanlab.com  Join Newsletter - https://hubermanlab.com/neural-network    Links: Dr. Sapolsky's most recent book, "Behave: The Biology of Humans At Our Best & Worst": https://amzn.to/3yrZ6k7  Support Research in the Huberman Lab at Stanford on Stress, Sleep & Human Performance: https://hubermanlab.stanford.edu/giving    Timestamps: 00:00:00 Introduction: Dr. Robert Sapolsky  00:02:26 Sponsors: Roka, Inside Tracker, Belcampo  00:06:30 Stress: Short & Long-Term, Good & Bad  00:09:11 Valence & Amygdala  00:11:00 Testosterone: Common Myths vs. Actual Truths  00:15:15 Behaviors that Affect Testosterone   00:17:20 Mindsets & Contexts that Affect Testosterone 00:20:28 How Finger Length Ratios Reflect Prenatal Hormone Levels   00:22:30 Aggression: Male-Female, Female-Male, & Female-Female  00:24:05 Testosterone: The Challenge Hypothesis  00:29:20 How Dopamine Impacts Testosterone & Motivation  00:32:32 Estrogen: Improves Brain & Longevity BUT TIMING IS KEY  00:39:40 Are Testosterone & Sperm Counts in Males Really Dropping?  00:42:15 Stress Mitigation & Our Sense of Control  00:51:35 How Best to Buffer Stress  00:57:04 Power of Perception, Choice & Individual Differences  01:00:32 Context-Setting, Prefrontal Cortex & Hierarchy  01:11:20 How Dr. Sapolsky Accomplishes Deep Thinking   01:13:17 Do We Have Free Will?  01:20:50 How to Apply Knowledge & Learning   01:23:44 Robert’s New Book: “Determined: The Science of Life Without Free Will”  01:28:27 Reflections, Support of Podcast, & Supporting Stress Research    Please note that The Huberman Lab Podcast is distinct from Dr. Huberman's teaching and research roles at Stanford University School of Medicine. The information provided in this show is not medical advice, nor should it be taken or applied as a replacement for medical advice. The Huberman Lab Podcast, its employees, guests and affiliates assume no liability for the application of the information discussed.