EP 769: Is Your Watch Lying? The Truth About VO₂ Max and Real Fitness

In this episode, we are joined by Cliff Pittman, Coaching Development Director for CTS.  We take a practical look at VO₂ max and what it really means for everyday runners. We explore whether this popular performance metric is truly essential, how much it matters for trail and ultra athletes, and where it can be misunderstood or overemphasized. The conversation cuts through the numbers to focus on what actually helps runners train smarter, stay healthy, and improve long-term performance. If you've ever wondered whether your VO₂ max score is a guiding light or just another shiny data point, this episode brings clarity and perspective from the trail. 

Key Topics

What is VO2 max and why does it matter for ultra runners? The accuracy and limitations of wearable VO2 max estimates How VO2 max relates to performance, aging, and training adaptability The concept of fractional utilization versus maximum effort Strategies for incorporating VO2 max training into your season Cross-training options like cycling and swimming for low-impact VO2 max work Monitoring progress with lab versus field testing and subjective feedback The importance of training variety and maintaining the entire aerobic engine Practical workout templates: intervals, recovery, and dosage over seasons How strength training and muscle mass influence VO2 max

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Timestamps

00:00 - Overview of the podcast topic: VO2 max importance for ultra runners
02:31 - Christian Blumenfeldt's unbelievable VO2 max of 101.1 — reality versus perception
03:26 - Simplified definition of VO2 max — oxygen consumption capacity of the body
04:43 - Limitations of wearable VO2 max estimates and lab versus field testing accuracy
05:34 - Why VO2 max is only part of the performance equation, not the whole story
07:13 - How VO2 max predicts short race performance but less so in ultradistance events
08:11 - The impact of fatigue resistance, durability, and fueling on ultramarathon success
09:31 - The significance of fractional utilization (operating below VO2 max ceiling)
10:13 - Can VO2 max be manipulated through training? Early season versus peak preparation
12:00 - The endurance spectrum: training both VO2 max and aerobic base for a well-rounded system
13:35 - Visualizing training as a string; raising ceiling versus improving utilization
14:34 - Should runners push to their VO2 max ceiling or focus on fractional utilization?
17:17 - Training strategies: balancing intensity, recovery, and avoiding injury during VO2 max work
20:04 - Substituting high-intensity VO2 work with cross-training (cycling, swimming) to reduce impact
21:28 - Monitoring other critical metrics: lactate threshold, recovery pace, subjective feedback
23:53 - The significance of individualized, periodized VO2 max training blocks
26:42 - The importance of patience, gradual progression, and listening to your body
28:55 - How to incorporate VO2 max sessions into your weekly plan: frequency, duration, and recovery
33:16 - The role of training specificity and modality as competition approaches
41:38 - Maintaining fitness and VO2 max as we age through consistent, varied training
43:33 - Linking strength training and lean muscle mass to VO2 max improvements
46:51 - Cross-training options and managing impact: cycling, swimming, hill repeats
48:37 - Final tips for beginners and experienced runners on starting VO2 max work safely
52:12 - The future of training: evidence-based approaches and coaching support at CTS