In this episode of the Critical Oxygen podcast, Dr. Andri Feldman and I discuss the importance of oxygen and how to measure oxygen dynamics in the muscle using near-infrared spectroscopy (NIRS) devices like Moxy Monitor. We explain the physiology of oxygen and its role in energy production through ATP synthesis. We also explore the different energy systems involved in exercise, including the phosphagen system, glycolytic system, and oxidative mitochondrial system. The conversation highlights the interconnectedness of these systems and the role of lactate as an intermediary. We then explore the principles of NIRS and how it measures oxygenation levels in the muscle. Overall, NIRS is a valuable tool for monitoring and optimizing training performance. TAKEAWAYS - Oxygen is crucial for energy production through ATP synthesis in the body. - The phosphagen, glycolytic, and mitochondrial oxidative phosphorylation systems are the three main energy systems involved in exercise. - Near-infrared spectroscopy (NIRS) devices like Moxy Monitor can measure oxygen dynamics in the muscle and provide insights into an athlete's performance. - Near-infrared spectroscopy (NIRS) measures oxygenation levels in muscles and can be used to determine steady state and critical power or even functional threshold power (FTP). - NIRS provides real-time feedback on oxygen supply and demand, allowing athletes to adjust their training intensity accordingly. Enjoy! Enjoying these podcasts, subscribe to get notified when new episodes are released. If you have a question or topic you want us to address, leave a comment! Follow Phil on Instagram - https://www.instagram.com/criticalo2 Interested in learning more about physiology? Check out the critical oxygen website for blogs, courses and coaching -https://www.criticaloxygen.com/ CHAPTERS 00:00 Introduction 07:10 The Importance of Oxygen and Energy Production 19:31 The Three Energy Systems in Exercise 25:20 The Role of Lactate as an Intermediary 38:26 Measuring Oxygen Dynamics with NIRS 42:19 How NIRS Works 43:41 The Importance of Oxygenation and the Role of NIRS 45:08 Understanding Muscle Oxygenation and NIRS Measurements 46:03 Using NIRS to Measure Oxygen Supply and Demand 47:23 Interpreting NIRS Readings and Muscle Oxygenation Levels 48:20 The Relationship Between NIRS and Oxygen Delivery 51:22 The Significance of Steady State in Exercise Physiology 52:49 The Importance of Maximal Sustainable Exercise Rate 56:07 The Relationship Between Oxygenation and Lactate Production 59:44 Comparing NIRS and Lactate as Performance Metrics 01:04:19 Using NIRS to Determine Training Zones and Thresholds 01:08:04 The Benefits of NIRS for Training Optimization 01:19:24 Triangulating Data Sources for Informed Training Decisions KEYWORDS oxygen, near-infrared spectroscopy, NIRS, energy systems, ATP synthesis, phosphagen system, glycolytic system, oxidative mitochondrial system, lactate, near-infrared spectroscopy, NIRS, oxygenation, energy systems, lactate production, muscle fatigue, steady state, critical power, training intensity, monitoring, optimization