Garmin Guru Deep Dive: Decoding the Internal Response to 4-Minute VO2max Intervals

A consolidated physiological data graph of a 5x4 minute VO2max cycling session, showing overlapping data for VO2 consumption, Moxy SmO2 (muscle oxygenation), heart rate, and power output.

Garmin Guru Deep Dive: Decoding the Internal Response to 4-Minute VO2max Intervals Today’s session of 4-minute VO2max intervals was a masterclass in why I lead with physiology, not physics. As the Garmin Guru at Online Bike Coach, I’m constantly looking for the “truth” behind the numbers. Today, that truth was found in gas exchange and […]

Garmin Stamina VO2 Threshold: Mapping the Fatigue Trigger

A multi-metric physiological graph showing the decline of Garmin Stamina during 2x14 minute 22/8 cycling intervals alongside SmO2, DFAA-1, and VO2 data.

Garmin Stamina VO2 Threshold: Mapping the Fatigue Trigger In my ongoing pursuit of the “Physiology First” training approach at Onlinebikecoach.com, I have used the Garmin Stamina VO2 Threshold to map exactly where my internal stability ends and metabolic exhaustion begins. To build a more resilient aerobic engine, I need to know my limits. With my […]

Living in the Parabolas: My Deep Dive into the “VO2 State”

Cyclist on an indoor trainer wearing a VO2master metabolic mask during a Billat 90/90 interval session with a Garmin 1040 and camera setup for data documentation.

Living in the Parabolas: Decoding Metabolic Inertia and the Billat 90/90 In our last deep dive, we dissected the steady-state grind of 5×3 and 4×8 intervals. Those workouts are the bread and butter of threshold development. However, today we are stepping into the “red zone” to explore Veronique Billat’s 90/90 Metabolic Inertia. Using the combined […]

Physiological Threshold Vs. FTP: The Power Illusion

Graph of SmO2, VO2, and power data showing physiological threshold during 4x8 intervals.

The Power Illusion: Resetting 20 Years of Training with Physiological Data After 20 years of cycling, I realized my FTP wasn’t telling the whole story of my actual physiological threshold. My identity as a cyclist was defined by a single, flickering number on a head unit: Watts. If you’ve spent any significant time in the […]

The Physiological Perspective of Four Separate 8-Minute Intervals

4x8 minute intervals online bike coach richard wharton coach wharton garmin connect

8-Minute Intervals At “Threshold”… In late November of 2024, I was able to perform an interval session on my indoor trainer and bike with my clients. The workout comprised of four separate 8-minute intervals. We used the VQ Velocity app, and I recorded each interval as a separate file while wearing my Vo2Master Gas Exchange […]

Vo2Master Vo2Max Value Affirms Garmin Vo2Max Estimator

Richard Wharton Vo2Master OBC Headquarters

Vo2Master’s Vo2Max Value Was 98% Consistent with Garmin In May of this year, I wrote a post about the Garmin Vo2Max Calculator. In July, I was able to test my Vo2Max at OBC Headquarters, to compare values. I performed a Graded Exercise Test, using the Vo2Master app. This app, on a cell phone, trapped data […]

Vo2Max On Garmin Connect and the Garmin 1040

Vo2max on Garmin Connect is closely correlated with Vo2max on a Gas Exchange analyzer.

Vo2Max Calculations Show Cardio-Vascular Changes Vo2max is a fitness and health measurement that is defined as, “The Maximal Volume of Oxygen that can be consumed by a person during physical exertion.” I’ve discussed Vo2max in the past, and I even own a Vo2Master assessment device, for testing and training purposes. Garmin Connect uses information collected […]

Fitness HRV software Release 0.17

Fitness ECG shows V2 and V3 data from a Polar H10 heart rate strap

Fitness HRV Now Includes Moxy SmO2 Values My work with Dr. Bruce Rogers and Mr. Stuart Lynne is continuing to show steady progress. Last month, I revealed the Alpha version of Fitness Dashboard. Fitness HRV is software that we are building to identify training intensities below VT1 (Ventilatory Threshold), and above VT2 (Traditional Threshold). The […]

Billat 30-30’s – Part Two

Billat 30-30s With SmO2 Shoulder and Leg

“Billat 30-30’s are intervals that require a hard effort for 30 seconds, followed by an easy recovery for 30 seconds. Over time, the body ends up playing ‘catch-up’, through heart rate, breath frequency, demand for oxygen at the muscular level, and a buildup of lactate in the system. 

We can see this buildup through lactate testing, which is invasive and cumbersome, but we can also see it through SmO2 values, as muscles de-saturate and re-saturate. Lactate is getting processed back into energy, but sometimes the demand for oxygen is greater than the body’s ability to provide it. “