In this episode of the Critical Oxygen podcast, Dr. Marco Altini and I discuss heart rate variability (HRV) and its applications in optimizing physiology and athletic performance. HRV is a measure of the variation in heartbeats over time and is influenced by the autonomic nervous system's response to stress. Dr. Altini emphasizes the importance of measuring HRV consistently and understanding individual baseline values and trends. He recommends measuring HRV every day if possible, but at least three to five times per week. When choosing an HRV device, it is important to consider the accuracy and reliability of the measurements. Dr. Altini also highlights the significance of stability and resilience in HRV, rather than focusing solely on higher values. Finally, we discuss strategies for improving HRV, including prioritizing sleep, managing stress, and making lifestyle modifications. TAKEAWAYS 1) Measure HRV consistently to understand individual baseline values and trends. 2) Choose an HRV device that provides accurate and reliable measurements. 3) Focus on stability and resilience in HRV, rather than aiming for higher values. 4) Use HRV as a feedback loop to optimize stress management and training. 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 Follow Marco on Instagram - https://www.instagram.com/hrv4training/ Or check out the App: https://www.hrv4training.com/ CHAPTERS 00:00 Introduction to HRV and Marco Altini 06:40 Understanding Heart Rate Variability 09:39 Factors Affecting HRV 13:25 Measuring HRV: Morning vs Night 16:19 Choosing a Protocol and Sensor 24:16 Interpreting HRV Values 29:46 Stability and Resilience in HRV 32:36 Using HRV to Inform Training 44:30 Frequency of HRV Measurement 46:48 Choosing an HRV Device 49:18 Improving HRV: Basics and Stress Management 51:43 Chasing Stability, Not Higher HRV 52:11 Interpreting HRV Variability 53:04 Factors Affecting HRV During Rest Days 54:01 Possible Factors for HRV Decrease During Rest Days 55:27 Effects of Diet and Hydration on HRV 56:50 HRV Changes and Athlete's Response to Training 57:49 Long-Term Changes in HRV and Heart Rate 58:47 Seasonal Changes in HRV and Heart Rate 01:01:38 Unusual HRV Patterns After Hard Sessions 01:03:31 Getting Started with HRV Monitoring