For men, testosterone is important for mood, bone health, erectile function, libido, strength and muscle mass and is also associated with lower levels of inflammatory markers, better insulin sensitivity, and metabolic health. It also may even have some vasodilatory effects, and higher testosterone levels are also associated with better health outcomes in general and lower cardiovascular, cancer, and all-cause mortality. Unfortunately, It looks like testosterone levels in the population are dropping, although more isn’t necessarily better. On this podcast, NBT Scientific Director Megan Hall and I are talking about testosterone: why we should care about it, how to test for it, and how to support healthy levels of this hormone. Megan discusses signs and symptoms of low testosterone and seven different lifestyle changes you can make to support optimal levels - before you even consider taking a supplement. We also talk about hormone replacement therapy, who might benefit, and some of the downsides to this strategy. For all the references and a detailed roadmap of everything we discuss, be sure to follow along with Megan’s outline for this podcast.  Here’s the outline of this episode with Megan Hall: [00:00:24] Testosterone: Why you should care. [00:01:49] Megan's outline for this podcast. [00:02:46] Optimal reference range for Testosterone. [00:03:51] Symptoms of low testosterone. [00:04:25] Testing for testosterone. [00:07:02] High testosterone is associated with violent crime. Study: Dabbs Jr, James M., et al. "Testosterone, crime, and misbehavior among 692 male prison inmates." Personality and individual Differences 18.5 (1995): 627-633. [00:07:32] Book: Behave: The Biology of Humans at Our Best and Worst, by Robert Sapolsky. [00:08:22] The testosterone suppression system. [00:08:35] Book: The WEIRDest People in the World, by Joseph Henrich. [00:10:13] Book: Mothers and Others: The Evolutionary Origins of Mutual Understanding, by Sarah Blaffer Hrdy. [00:12:02] Testosterone physiology; troubleshooting by testing LS and FSH. [00:14:38] Varicocele - the enlargement of veins within the testicles - common amongst athletes. [00:16:31] Sex Hormone Binding Globulin (SHBG) [00:19:44] How to support testosterone levels. [00:20:41] 4-Quadrant Model; Josh Turknett's AHS talk: How To Win At Angry Birds: The Ancestral Therapeutic Paradigm - AHS19. [00:20:55] Josh Turknett on the NBT podcast: How to Win at Angry Birds: The Ancestral Paradigm for a Therapeutic Revolution [00:21:11] Sleep; Greg Potter on the podcast talking about sleep: Why Sleep Is Critical for Immune Health, How to Entrain Your Circadian Rhythm for Perfect Sleep and Metabolic Health, Better Sleep for Athletes, and What to Do When You Can’t Sleep. [00:21:33] Sleep deprivation decreases testosterone; Study: Leproult, Rachel, and Eve Van Cauter. "Effect of 1 week of sleep restriction on testosterone levels in young healthy men." Jama 305.21 (2011): 2173-2174 and Gonzalez-Santos, M. R., et al. "Sleep deprivation and adaptive hormonal responses of healthy men." Archives of andrology 22.3 (1989): 203-207. [00:22:26] Greg Potter's articles on sleep: 1. Having trouble sleeping? A primer on insomnia and how to sleep better 2. Sleep-maintenance insomnia: how to sleep through the night 3. Sleep-onset insomnia: how to get to sleep fast.  [00:22:37] Stress; Chronic stress in particular, more so than acute stress. [00:24:54] Podcast: How to Manage Stress, with Simon Marshall, PhD. [00:25:09] Eating sufficient calories. [00:26:13] Podcast with Herman Pontzer: How We Really Burn Calories, Lose Weight, and Stay Healthy. [00:27:57] Nutrient deficiencies: zinc, magnesium, vitamin D. [00:29:30] Cholesterol and dietary fat. [00:30:51] Exercise. [00:33:32] Within day energy availability can negatively impact the testosterone:cortisol ratio; Study: Torstveit, Monica Klungland, et al. "Within-day energy deficiency and metabolic perturbation in male endurance athletes." International Journal of Sport