From power breathing to underwater workouts to Wim Hof-style cold water immersion to sexy Training Masks to freediving, spearfishing and beyond, it seems that performance breathwork is taking the world by storm. In today's podcast, I take a deep dive with performance breathing expert Brian Mackenzie. Brian is a strength and conditioning and movement expert, and creator of CrossFit Endurance (which I interviewed him about way back in ) He co-authored the book “", recently co-authored “” and works with professional and elite level athletes in running, cycling, rowing, MMA, MIL/SOF, LEO, Fire/EMT, surfing, paddling, swimming, CrossFit, including Olympic Gold Medalists and World Champions. Brian and his programs have been featured in Competitor Magazine, Runners World, Triathlete Magazine, Men's Journal, ESPN Rise, The Economist, Tim Ferriss' New York Times bestseller The 4-Hour Body, Men's Running UK, LA Sport & Fitness, Muscle & Performance Magazine, and Rivera Magazine. During our discussion, you'll discover: -The true science behind the Training Mask, and whether it actually works... -How to use oxygen and carbon dioxide static apnea tables... -Why so many freedivers and spearfishers are dying from shallow water blackouts... -The uncommon restricted breath training devices Brian uses in his clinics... -How to use hyperoxia... -Where to start if you want to hold your breath for four minutes... -And much more! Resources from this episode: - -(use code GREEN1 for 20% discount) - (use code BGF025 for 25% discount) - - - - - Do you have questions, comments or feedback about performance breathing? Leave your thoughts at and either Brian or I will reply!