This episode I discuss the hormones testosterone and estrogen and how they impact the brain, body, and behavior at ages after puberty. I also discuss how various behaviors such as exercise (resistance and endurance training) and sex, or observing sex impact these hormones and their levels. I ask: "what specifically is it about such activities that impacts testosterone and estrogen?"; the resounding theme is that when our nervous system is activated in particular ways it drives our endocrine system and vascular system to activate or repress certain hormone networks in predictable ways. I also discuss peer-reviewed studies and protocols addressing (at a mechanistic level) how light, cold and heat, and respiration (breathing) can positively or negatively impact testosterone and estrogen. And we discuss specific supplements and compounds that peer-reviewed studies illustrate can adjust testosterone and estrogen levels: by changing their binding to other proteins, by raising them directly, or by changing other hormones released from the brain and pituitary. I discuss optimization in the normal reference ranges for these hormones, and I discuss pheromones, apnea, menstrual cycles, menopause and andropause. As always a mix of basic science, biological mechanisms and tools and protocols are discussed. **Note: Future episodes will focus on the science of prescription hormone replacement therapies, the science of hormone-based birth control and the role of testosterone, estrogen and other compounds in fertility, athletic performance and recovery.   Thank you to our sponsors: Four Sigmatic - http://foursigmatic.com/huberman Blinkist - http://blinkist.com/huberman Theragun - http://theragun.com/huberman   Bloodwork sponsor: InsideTracker - http://insidetracker.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   References: http://examine.com “Behavioral Endocrinology” by Nelson and Kriegsfeld 5th Ed. Timestamps: 00:00:00 Introduction 00:05:50 Hormone Optimization 00:07:00 Salutogenesis: A Powerful Way to Conceptualize Health 00:10:03 Estrogen and Testosterone: Sources, Levels & Ratios 00:15:46 The Power of Competition, Plus: Anxiety, Persistence & Dopamine 00:20:58 Testosterone & Libido Pre-Ovulation 00:21:48 Estrogen & Sexual Receptivity; Libido In Males 00:23:10 How Sex Behavior Impacts Testosterone: Observing vs. Actual vs. Abstinence 00:26:46 Testosterone & Prolactin: Sex Seeking vs Pair Bonding 00:27:30 DHEA (dehydroepiandrosterone): Effects on Levels/Ratios 00:28:45 Behaviors That Decrease Testosterone (& Cortisol): Parenting & Prolactin 00:31:24 How Illness Impacts Testosterone & Estrogen: Cytokines, e.g., IL-6 00:33:20 How Exactly Do Behaviors Change Hormones? 00:34:18 Pheromones: Miscarriage, Menstrual Cycles, Puberty Onset, & Mate Recognition 00:43:33 Apnea: A Powerful Bi-Directional Influence On Estrogen & Testosterone 00:47:44 Mouth vs. Nose Breathing & Hormone Levels: Effects Via Sleep and Direct Effects 00:51:11 How Sleep Adjusts Cortisol/Testosterone and Cortisol/Estrogen Ratios 00:53:49 02:CO2 Ratios, Nasal Breathing During Exercise 00:56:30 Light Viewing Patterns & Hormones: Dopamine, GnRH 00:57:44 Spring Fever: Tyrosinase, Hair Color, Mating Frequency 01:04:39 Specificity of Hormone Effects 01:06:03 Temperature: Cold & Hot Gonads 01:14:10 How To Exercise: Types, Effort Level, Sequencing 01:21:42 Cardio/Endurance vs. Resistance Training (First or Last?) Yes, It Matters 01:24:41 Estrogen & Menopause: Compounds That May Ameliorate/Reverse Symptoms 01:33:18 Nutrients That Optimize The Foundation For Hormones 01:36:00 Opioids as Severe Hormone Disruptors 01:37:23 Testes, Antlers & Ovaries 01:38:50 Creatine & Increasing DHT (Dihydrotestosterone) 01:40:14 Free and Bound Testosterone: SHBG (Sex Hormone Binding Globulin), Tongat Ali 01: