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Vo2Max and Heart Health – A Single Ride Following Dr. Paddy Barrett’s Formula

Vo2Max and Heart Health Correlation With DFAA-1 and other Metrics

DFAA1 and SmO2
When we flip the script on wattage, and instead focus on heart health, we have a host of new metrics we can observe and track to ensure compliance.

I recently stumbled across a Substack post by Dr. Paddy Barrett that explains how Vo2Max is impacted by low intensity exercise. While I had not known about Dr. Barrett previously, when I read his history and other posts, I became intrigued. I think he’s a world-renowned Cardiologist who focuses on heart health, and his posts discuss exercise, diets, supplements and lifestyle recommendations. In a way, I’m reminded of Dr. Ken Cooper of the Aerobics Institute, but Dr. Barrett is about half Dr. Cooper’s age.

The article I am referencing for this post discusses Vo2max, and ways to raise that value. But Dr. Barrett makes a unique argument. The article states that there are ways to RAISE Vo2max, but there is a different way to obtain your HIGHEST Vo2Max. They’re different things. Honestly, I had never thought of Vo2Max in this way, so I dug deeper.

Raising Vo2Max Is All About INTERVALS

Vo2max and SmO2 Intervals
The area in black is a rolling 30-second view of my Vo2max, per the Vo2 Master. The area in red is my saturated muscle oxygen on my left lateralis. The goal is to find something we can use in the field, to equivocate with the data I acquire in the lab.

Intervals. Boy, do I know a lot about intervals. Short-Sharp, Medium-Hard, Tabata, Zonneveld, 2×20’s, Fibonacci’s, Reverse-Fibonacci’s. I know Intervals. Intervals are hard. They strain the cardio-vascular system. They FEEL like results. Intervals are NOT boring.

Intervals, especially intervals that are inside of, say, six minutes in duration, will improve Vo2Max over time. I routinely perform six-to-eight-week blocks of Vo2Max efforts to raise not just my Threshold for economy (another metric that benefits from Vo2Max intervals), but also my ability to perform in the Supra-Threshold Realm. This level of intensity creates a massive bath of lactate, and requires a LOT of MCT1’s and MCT4’s (Monocarboxylate Transporters) to convert that lactate back into energy. Vo2Max efforts build those MCT1’s and 4’s, and they grow the muscles of the heart as well.

Vo2Max Intervals will raise Vo2Max… relative to an original value…

But not two sentences later, Dr. Barrett talks about the ‘Other’ component of Vo2Max; the highest overall value a cyclist can obtain. So intervals improve Vo2Max, but they don’t necessarily help you achieve your highest possible overall value.

Achieving Your HIGHEST FEASIBLE Vo2Max… Is All About BASE TRAINING!

Base. I write about it. I try to achieve it with AlphaHRV and DFAA-1, both for myself and my clients. I use a Moxy Monitor to observe muscle oxygen percentages that correspond with Ventilatory Threshold 1 and Ventilatory Threshold 2. We also study basic, old-fashioned heart rate, and of course, power/watts.

Dr. Cooper called it ‘LSD’, for Long, Steady Distance. The popular term these days is ‘Zone 2’. It’s an intensity that is assertive, but not overly so. It’s aerobic. It relies on fat for the majority of the fuel that is used.

But Dr. Barrett has one comment in the article that stands out…

“Stroke volume and left ventricular dilation are at their maximum between 40 – 60% of V02 Max 6.

Above 60% of V02 Max, stroke volume decreases, and the heart does not reach its full dilation capacity (LVEDD).

For most people, 40 to 60% of V02 Max is a relatively low intensity.

Usually a good big serving of Zone 1 and some Zone 2.

As you train these zones, your resting heart rate will decrease.

Therefore, for each heartbeat, your heart will fill even more, and the heart will dilate even more.

This intensity is where most people should be spending most of their time.”

And it’s the BOLD part that really struck me.

I can actually measure 40-60% of Vo2Max on my Vo2Master. Furthermore, I’ll pair that metric with traditional heart rate, DFAA-1, Muscle Oxygen, Power, and even cadence, to assess just what those values are in relation to that Vo2Max range. It’s a study of N=1, with a workout count of N=1, but if the numbers correlate with my own observations from previous rides, then it’s an affirmation that all my geek measurements are actually valid… at least for me.

Let’s Take A Ride.

On January 5th, 2025, I rode a ‘Base’ ride with my clients on VQ Velocity. I used the Vo2Master mask, a Moxy Monitor, the AlphaHRV Field on a Garmin 1040, and a power meter.

You can find this ride and others in an app that a client, Kenneth O’Brien, built for me so that we could assess this information in this way.

JUST CLICK HERE.

For this ride, the file in the drop-down menu reads ‘RW-01-05-25-drp-protocol‘.

I used the mask for about 28 minutes of the effort. The mask was calibrated with a 3 liter plunger, and was calibrated for O2.

Based on efforts in late December, I am highly confident that my Vo2Max (IN INTERVALS….!) is about 60ml/kg/min (See the file dated ‘RW-12-22-24’ in the app).

40% of 60ml/kg/min = 24

60% of 60ml/kg/min = 36

For the Best twenty minutes of this ride, here are my averages…

Coach Richard Wharton Base Ride Vo2 Values
Here’s the information from the file, using Vo2 as the max average basis. Based on a previous post, I believe my VT1 Threshold for traditional heart rate is about 140 bpm. Alpha 1 is usually higher than 1.11 at 136. This is the first indicator that Dr. Barrett’s referral to 40-60% of Vo2max is spot on.

This next image changes the ‘Max Average Basis’ to traditional heart rate, which just serves to shuffle the columns a bit, to make it easier to see the data.

Richard Wharton Vo2Master Paddy Barrett Zone 1 Zone 2
Vo2 stayed right at or below the 60% value, while heart rate and power were solidly in my perceived aerobic zone of intensity.

Now – let’s look at DFAA-1 via AlphaHRV:

If you read through this blog post from November of 2024, you’ll see that the values on the charts above are very similar to the charts and averages from two months earlier.

  • VO2 for that base ride was 38ml/kg/min. That checks with the 40ml/kg/min upper limit.
  • Average heart rate was 136 beats per minute. This is the same.
  • Average power was 170 watts in November, and 166 watts in January. This is VERY similar.
  • DFAA-1 averaged 1.34 in November, and it averaged 1.19 for this ride. Both values are above my stated goal of 1.10 or even 1.15.
Average AlphaHRV value 20min dfaa-1
Alpha 1, calculated by AlphaHRV app on the Garmin head unit, has me at a 1.19. Anything above a 1.10 or 1.15 for me, is Aerobic.

 

CONCLUSION

Dr. Paddy Barrett’s article states that the heart chambers will dilate more fully at an intensity between 40 and 60% of Vo2max. However, it’s hard to get Vo2 values because of the cost of the equipment.

Therefore, we need to determine whether other methods of physiological tracking are equally valid.

  1. Vo2 for the effort was just under 60%. CHECK.
  2. Traditional Heart Rate was below 140bpm, which an earlier blog post determined was the upper limit of my VT1 breakpoint. CHECK.
  3. AlphaHRV recorded an average DFAA-1 at 1.19, which is above the 1.10-1.15 value that I have determined is the equivalent breakpoint for Threshold 1. CHECK.
  4. Traditional wattage was about 170 watts, give or take. This is below my self-prescribed Threshold 1 as well. CHECK.

I think we can safely affirm that the combination of using AlphaHRV, Traditional Heart Rate, and maybe a rolling 30-second view of wattage, will give us a high level of confidence that we are safely and effectively cycling to improve Vo2Max. Following AlphaHRV values allows my athletes to ride for the most effective value OF THAT DAY. This eliminates Physics (wattage), and emphasizes recovery, hydration, fatigue, temperature, and more. Let’s go with the Physiological parameters for accuracy; we can worry about performance later.

Thanks for reading, and

#ENJOY THE RIDE!

 
 

The Physiological Perspective of Four Separate 8-Minute Intervals

8-Minute Intervals At “Threshold”…

4x8 minute intervals online bike coach richard wharton coach wharton garmin connect
Wattage, heart rate, and Saturated Muscle Oxygen do not always agree. In this blog post, I dive into the physiology of EACH INTERVAL, which gives me greater insight into how to improve workouts for myself and you.

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 Analyzer. Then, one of my clients, Ken O’Brien, actually coded an app that would allow me to compare the intervals against each other.

Traditional Interpretations of 8-Minute Intervals

When I look at the data from a ride file, I usually use graphs and charts from Garmin Connect. When I ride, I use a Garmin 1040 and the lap button, to assess real-time information. For years, I used wattage and traditional heart rate for each of the 8-minute intervals, but with advanced Heart Rate Variability Analysis, I can now include EPOC, aerobic and anaerobic training effect, and DFAA-1. These values USUALLY yield enough information to determine whether I’m achieving my training goals or not.

 
 

Inclusion of Gas-Exchange Analysis in 8-Minute Intervals

Vo2Master App Metrics
This is just one page of data fields that I can use on the Vo2Master app. You can also run these fields as graphs. All of the data is stored in a detailed .csv file that can be downloaded and shared for analysis.

By including data from my Vo2Master gas-exchange analyzer, I wanted to determine whether these traditional metrics were accurate and valid. It’s one thing to get a ‘Score’ or an interpretation of training results from a software with algorithms. These are usually pulled from a EULA that traps metadata and makes suppositions about intensity, dose, and recovery. I find these interpretations to be… shallow. Hence, the need to pull data from the body. 8-minute intervals are long enough to measure metabolic changes via data that I can only get from a breath-by-breath analysis. The goal is to MELD traditional, on-bike data that I can get from my Garmin, with the knowledge gained from the Vo2Master, Moxy monitor, and AlphaHRV.

8-Minute Interval Data

Here’s the link to the 4 x 8-minute interval efforts, along with a chart showing ‘traditional’ averages for Garmin Metrics.

And here is my first summary of the information that I collected.

LapAve HRAve CadenceTorque EffectivenessAve PowerSmO2ThB
11689685%24913.645%12.408
21679584%23815.378%12.369
31659185%23216.307%12.364
41689284%22814.434%12.371

This was where I first began to suspect that some of the ‘Traditional’ parameters for an 8-minute interval might not be as effective as decades of efforts had led me to believe. Now – here is the data from the Vo2Master… Let’s first look at Heart Rate vs. Heart Rate.

This is the graphical data for traditional HR, using the First interval as the benchmark, in black. The following intervals are in red.

For those who are interested, THIS LINK will provide access to these files. For this blog post, the files I’m using are found under ‘select dataset directory’, and are the following:

  • ./Data/RW-11-28-24-Int1
  • ./Data/RW-11-28-24-Int2
  • ./Data/RW-11-28-24-Int3
  • ./Data/RW-11-28-24-Int4

You can certainly play with any of the files, however.

Vo2master heart rate vs heart rate chart 1
Heart rate for the first 8-minute interval is in black. Heart rate for the second interval is in red. You can see a similar pattern.

Here’s the chart comparing the first interval to the third 8-minute interval.

o2master heart rate vs heart rate chart 2
Again, once I get set into the effort, traditional heart rate follows a similar path.

For the fourth interval, there was something that interfered with my final 30-seconds, so the effort was cut slightly short. However, for the 6-minutes in the middle, again, traditional heart rate is similar. Refer to the above table to see just how close the heart rate averages were.

Heart Rate vs. Vo2

Now – here’s a table showing traditional on-bike metrics vs. Vo2Master metrics for each 8-minute interval.

LapAverage Vo2Heart RatePower AverageRespiratory RateSmO2ThB
146.531682494013.645%12.408
244.631672383915.378%12.369
341.981652323516.307%12.364
441.171672283714.434%12.371

And here are some charts comparing different metrics from one interval to the next. Again, I’ll use Interval #1 as the benchmark.

Online Bike Coach Vo2Master 8 Minute Intervals Compared n1
This is a Vo2 comparison of my first and second 8-minute Interval. Black is the first interval, red is the second. The averages are on the table above.

Here’s the first interval against the third interval…

Online Bike Coach Vo2Master 8 Minute Intervals Compared n2
Again, the first interval is in black, while the second is in red. I lost Vo2 intensity and efficiency for roughly equivalent heart rate.

And here’s the first interval against the last interval…

Online Bike Coach Vo2Master 8 Minute Intervals Compared n3
And finally – here’s the last of the four 8-minute intervals. Vo2 was suppressed, as was wattage, but heart rate was not.

Vo2 vs. SmO2 for the 8-Minute Intervals…

Now remember – we’re looking at what wearables are telling us, vs. the outcome. These intervals really were NOT that great for me, but if I want to improve both results and consistency for the time requirement and demands, I really want to dig deep and look at all of the parameters. Here, I have placed Vo2 against SmO2 in the Left Lateralis. Take a look….

Online Bike Coach Vo2Master Moxy Monitor 8 Minute Intervals Compared n1
Rember to use the table a few paragraphs up. There, you’ll see my average SmO2 for each interval. In my opinion, I went WAY too hard for most of the intervals, and ended up fatigued out, which affected the other three efforts. Let’s continue…

Here’s 8-minute interval number 2.

Online Bike Coach Vo2Master Moxy Monitor 8 Minute Intervals Compared n2
This interval is unique because you can see how ‘backing off’ on the intensity, lowered my Vo2, and raised my SmO2, right around Minute 4 to 5. I think this is an important value, which I’ll point out in the following image….

I’m going to show 8-minute interval #2 again, this time with wattage instead of Vo2.

Online Bike Coach Moxy vs wattage 8 Minute Interval n2
I love looking at SmO2 from my Moxy, because it’s consistent, sensitive, and is a fair proxy for VT2 and/or LT2. As you can see, when power (Vo2 is in the previous image), drops as a result of less effort, SmO2 rises, allowing me to witness and recover without losing too much power or intensity. When I rally, Smo2 drops again, but I am better able to find a ‘sweet spot’ of intensity that leads to a sort of ‘Plateau’ for saturated muscle oxygen. By the way – the drop in power at the end is from a hard shift that forced me to stand. It messed up the readings. Don’t Do This!

Here’s the third of the 8-minute intervals, comparing Vo2 to Smo2…

Online Bike Coach Vo2Master Moxy Monitor 8 Minute Intervals Compared n3
By the third interval, I had kind of nailed down the intensity that I was going to be able to sustain more appropriately. Vo2 is more consistent, while SmO2 range is also more consistent.

Now, the 4th 8-minute interval was wonky, and if you look at the right side axis, you’ll see that the scaling is off. You’ll need to refer to the tables, but suffice it to say – SmO2 was fairly low, wattage was compromised, and Vo2 was also compromised. My own interpretation is that I was knackered; fatigued; out of sugar; bonking. But honestly, I don’t really have an answer.

Online Bike Coach Vo2Master Moxy Monitor 8 Minute Intervals Compared n4
Not much to say here, other than I believe the SmO2 sensor CAN give a clear picture, on a Garmin head unit, of those liminal states of intensity, below which (higher SmO2 %) you’re safe, and above which (lower % SmO2), you’re on ‘borrowed time’. I pretty much hit the ‘sweet spot’ via Smo2 (demand) at about the 5-minute mark.

Now, here’s the Crux…

If we use some of these ALGORITHMS that claim to ACCURATELY PREDICT Threshold Power, Functional Threshold Power, VT2, LT2, Critical Power, or whatever, then we depend on them for accuracy, consistency, and repeatability.

But when you look at my tables, and then the graphs, this really is not as accurate as one might be led to believe. The two that I have used extensively in the past, which I won’t name, have my ‘Threshold’ at 270 watts, and 172 beats per minute, per traditional heart rate. These interval intensities were nowhere close. Since 2003, when I first began programming interval sessions for clients using WordPad, I’ve always understood that wattage cannot be the end-all, be-all to training. We have to look at things Holistically.

These wearables, like a Moxy and a modern Garmin or Polar Chest strap, along with 3rd-party Fields, like AlphaHRV (which I did NOT discuss in this post, but will in a follow-up), give us a price-effective way to gain greater insight into EVERY ride, EVERY INTERVAL, and even EVERY BREATH or PEDAL STROKE, down to the second.

I’ll post a follow-up to this post, with some more insights, but I’m at my limits of knowledge here. This is where the ‘Mad Scientist’ always loses out. I need a True Physiologist. Luckily, I’ve got two or ten who share my passion for these Deep Dives, and who can help me understand. I’ll share this information as soon as I can.

Thanks for reading, and

#ENJOYTHERIDE!

 
 

Rotor Q Rings Revisited – Yet Again

Rotor Q Rings DO Work – Just Not The Way You Might Think

I’ve been using Rotor Q Rings ever since they came out. Prior to that, I was using Rotor’s ‘RSX’ technology, because the company gave their product to trained scientists for honest review and application.

The theory behind Q rings is that they provide gains in power without costs in metabolic energy expenditure. I don’t think that’s exactly the best translation. Instead, I believe that they do two things…

  1. They provide just ‘that much more’ power in the Power Phase of a pedal stroke (it’s 2-6%, and it’s NOT 360 degrees; more like 70-90 degrees)… and…
  2. Based on the ovality (once a thing, now just standardized – no more QXL rings…), Rotor Q Rings can help Optimize the ‘Moment’ (Physics Term) where max torque can lead to those extra millimeters of power and thrust.

 

Q Rings Have Five Settings

Rotor introduced a method, way back in 2010, I believe, where a cyclist could figure out just where the highest torque occurred in a pedal stroke, in relation to the crankarm. In an ideal world, this torque occurs at the highest ‘Moment’ of a pedal stroke. In other words, if a crank of 170mm was riding at 0% slope, ideally, the “Optimal Moment” would also be at 170mm, at the 3 o’clock position, or 90 degrees, completely perpendicular to the force of gravity. Like a crowbar, a cyclist pushing a crank with their leg gets the best assist from gravity where the crankarm is longest.

But it doesn’t usually work that way.

Pedal strokes and power phases are unique to the individual. You have to look at ‘Moment’. If the Rotor InPower Software shows that your ‘Optimal Moment’ is slightly above or below 90 degrees, well, that’s where the Q Ring can be beneficial. Move the Q Ring to the Optimal Chainring Position, and you’ve Optimized your power output.

Gravity Always Wins – But Torque Helps

When Pablo Carrasco, the inventor of Rotor Products, started looking at the physics of pedaling, he noticed some things.

  1. If a crank and chainring achieve OCP at 0% slope, the value might be different at different slopes.
  2. The contact point where chain and ring meet is always at 0 degrees. But having ‘Optimal Moment’ at 90 degrees at 0% slope in relation to the bike, would have you at ‘Optimal Moment’ of 80degrees (OCP 2) at a 5 or 6^% slope.

The goal for Rotor Q Rings should be to ‘Optimize’ the Chainring for torque based on the slope you want to optimize. If you’re a sprinter, well, the study I remember from Pez Cycling showed that while Max Power was not significantly altered, the rate at which Max Power was achieved was statistically significant. The study also showed that Rotor Positions 4 and 5 (with the crank near 4 0’clock position), was ‘Optimal’. Ironically, ‘Moment’ for a 170 mm crank at 4 o’clock position would be around 150mm, effectively, a shorter crank….

When I used the Rotor InPower system on my Mountain bike earlier this year, the OCP recommendation for a roughly 5% slope was OCP 4. I truly can ‘feel’ the torque on steep climbs, and as I age, I continue to rely on every mechanical advantage I can possibly hold.

Rotor Q Rings On A Road Bike In Hilly or Mountainous Terrain

The Rotor InPower Cranks that I have on my 2018 Cervelo date back to…. 2012??? 2015? I honestly don’t remember. When I raced, the terrain in Texas was rolling, punchy, and finishes were almost always flat or false-flat. I used the InPower software for PC, on rollers, to determine my Optimal Chainring Position (OCP), and came up with a ‘4’. I did not change it for eight years.

This year, upon my return to Reno, and having lost about two years of my outdoor cycling life to, well, life, I focused on my mountain biking. Now that winter has hit, and the trails will soon close, I’ll be riding out on the road more, as well as indoors. I decided to test my road bike, and reset my rings. This was done indoors, since that’s the only way I can ‘read’ the data from these cranks; they don’t

Here are the results:

At 0% slope, the Rotor Optimal Chainring Position (OCP) showed either Position 2 or 3, but from 1% slope up to 5% slope, when I quit the assessment, the InPower Software told me to place my Q Rings at OCP 2.

This MAY SOUND FAMILIAR.

Conclusion

So now I’m set. I’ve moved my Rotor Q Rings to OCP 2, and the next step is to find a way to measure OCP via the InPower APP, and affirm that ring position. Let’s go get some Marginal Gains. The Road Beckons! Watts Up!

Thanks for reading, and

ENJOY THE RIDE!

Vo2 at Threshold

Vo2 at Threshold – Affirming Outdoor Power at Threshold

Richard Wharton Vo2 at Threshold Online Bike Coach
Vo2 at Threshold can reveal a lot about how cardio-vascular fitness and status. The closer that number is to your Vo2Max, the better.

In my last blog post, I mentioned that for my best 10-minute effort while climbing a trail on a mountain bike, my Vo2 at Threshold read as roughly 55ml/kg/min. I also believed that my Vo2Max was roughly 62ml/kg/min. I was curious to see if these values were valid, so I went back indoors. At my home studio, I performed five weekly 20-minute efforts, specifically to determine whether those two values, Vo2 at Threshold, and Vo2Max, were accurate.

 

Percentage of Vo2Max When Cycling at Threshold Intensity

Different Metabolic Thresholds at a Percentage of Max Wattage
I’ve followed Jem Arnold for about a decade now, as he’s been involved in studying SmO2 for cyclists, as well as a lot of other things. This chart he presents, from a lecture, shows wide variation in ‘Thresholds’, where the body begins to migrate from mostly aerobic energy to anaerobic energy. This post is about Vo2 as a % of Max at Threshold.

There’s a lot of new information coming out about the determination of Training Zones. Essentially, each method of measurement tends to come up with its’ own value, and training zones are then based on those values. Let’s face it – Vo2 at Threshold is expensive to acquire, since it requires a Vo2Master, a Polar H10 chest strap, a Moxy, a Power Meter, and probably a Lactate Tester, which is a product I have owned in the past, but do not own at this time. Instead, I use the Moxy and other readings from the Vo2Master and my Polar H10 chest strap, to determine the most accurate Threshold value for myself.

By looking at ALL of the values, however, I could then apply each of them when training. If the goal is to raise Vo2Max to its’ highest time-limited potential, and to raise % of Vo2Max at Threshold, then having those other metric markers can help me take a more holistic approach to every ride.

The Workout

For these five tests (and probably counting), I used my standard indoor training software, PerfPro Studio. My warmup consisted of a 27-minute protocol that I’ve honed using Moxy muscle oxygen sensors. I did roughly four Vo2master O2 calibrations for each workout, but I only recorded the 20-minute effort on the Vo2Master app. The Vo2Master is best used in a consistent atmosphere, so I used a local 8000 btu air conditioner in my small room, to help keep humidity and temperature under control.

PerfPro Studio Vo2 at Threshold Workout
There’s literally no better piece of software in the cycling fitness world than PerfPro Fitness. The amount of information I can read, along with the myriad ways I can build workouts, remains unmatched.

Here are the results:

Date20Min Vo2 Average20Min Power Average20Min HR Average20Min RR Average20Min DFAA1 Average20Min SmO2 Average20Min EqO2 AverageBest 30-sec Vo2maxVo2 as a % of Max
6-Oct53.5271163350.56.822.262.685%
13-Oct55.1287172390.41524.560.691%
20-Oct57.5281170420.42024.565.288%
27-Oct56.9273172430.4310.225.363.290%
3-Nov56.9273172430.410.225.363.290%
AVERAGE55.98277169.840.40.42612.4424.3662.489%
HIGH57.5287172430.52025.363.291%
LOW53.5271163350.46.822.260.685%
RANGE416980.113.23.12.65%

What the Chart Says

There’s more information on this chart than just Vo2 values, but here’s the summary…

  • My 20-minute average Vo2 over 5 efforts was 56ml/kg/min. This is comparable to the 55ml/kg/min that was observed in the mountain bike climb from the previous, outdoor, post.
  • The highest 30-second Vo2 value over the same 5 efforts, which I’ll call Vo2Max, was 63ml/kg/min. Again – I’ve seen this ‘Vo2Max’ value enough to believe it is accurate. Incidentally, my Garmin 1040 and Garmin Connect continue to show my Vo2Max, per calculation only, at 59-60ml/kg/min, which I believe tracks pretty well, even though it is not using metabolic values, and instead uses calculations.
  • When you take the 20-minute Vo2 at Threshold, and divide it by the 30-second Vo2Max, well, my Vo2 at Threshold occurs at about 89% of my Vo2Max.

Notice that I have not mentioned power, or watts. I’ll explain why…

Vo2 at Threshold is a PHYSIOLOGICAL PHENOMENA

For 27 of my 31 years as a Professional Cycling Coach, pursuing watts at Threshold, watts at Vo2Max, and watts per kilogram per minute, has been a stated priority. However, Physics is immutable, while physiology is incredibly mutable.

For the same amount of physiological effort on the outdoor effort in the previous post, I averaged maybe 235 watts over 10 minutes, and 207 watts over 20 minutes. For these five indoor tests, I averaged about 277 watts over 20 minutes. The delta is too great to ignore.

On that same ride, I averaged 165 beats per minute for the climb, while on these five indoor rides, the average heart rate was 170 beats. Temperature, convection, and evaporation are important considerations for heart rate intensities.

For my climb outdoors, which was not 20 minutes, the average DFAA-1 on AlphaHRV was about a 0.4. For the 5 indoor efforts, it was 0.43. I am becoming more and more convinced that there is something ‘there’ there when it comes to DFAA-1 and Threshold.

Finally, the SMO2 value for my climb was about 25%, while the SMO2 average for the 5 indoor 20-minute efforts was 12.4%. I’m convinced that this is because of micro-recoveries on a mountain bike trail, vs. the consistent resistance of a 2% slope indoors.

I think I want to optimize my physiological markers going forward, and those of my clients, and let the watts take care of themselves from now on. Chasing watts as a primary metric, especially on a mountain bike, can leave a rider disillusioned and frustrated.

Conclusion

Vo2 at Threshold is a great way to assess your current fitness, but it requires expensive apparatus. I still don’t own all of the kit I could possibly wear that would help with this assessment. Knowing that my Vo2 at Threshold, is roughly 89% of my Vo2Max, does reassure me that my fitness, at least in August of 2024, and again in October of 2024, is pretty close to my genetic potential.

The next step, one I won’t attempt until the Spring of 2025, will be to try and grow that Vo2Max up to a 65, 66, or even 68ml/kg/min. This will be INCREDIBLY difficult to achieve as a 55-year old male, but I’d like to try. The next step would be to see if I can HOLD my Vo2 at Threshold near 90% as that Vo2Max rises. This is going to require losing another 2 kilograms of mass, maybe 3. That MAY affect my power output and fatigue levels, so I have to temper action with wisdom on this as we go into the 2025 PreSeason.

Winter is approaching quickly, and the cooler temps mean that I won’t be able to use the Vo2Master outdoors nearly as much. When the snow finally leaves the trails unrideable, I’ll be hyper focused on my indoor efforts in my VQ Velocity until Spring. But until then, I’ll be riding outside on the mountain bike on my beloved Peavine, trying to keep my singletrack skills and dreams alive until April 2025, when I can get back out there again.

I’ll post some follow up blogs about the other metrics featured in the chart above, but I need to consult with some PhD’s that are wiser than I am on these parameters. I also have to thank my client, Ken O’Brien, a retired Bell Labs professional, on his coding assistance for a new project that I’ll reveal next.

Thanks for reading, and ENJOY THE RIDE!

 
 

Vo2Master Vo2Max Value Affirms Garmin Vo2Max Estimator

Vo2Master’s Vo2Max Value Was 98% Consistent with Garmin

Richard Wharton Vo2Master OBC Headquarters
THE THINGS I DO FOR SCIENCE!

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 from multiple sources. The Vo2Master’s Vo2Max value showed a 1-point difference from the calculation to the actual results.

Let’s take a look at what I learned about myself.

Remember – Vo2 is translated into: ‘Volume of Oxygen Consumed’. It’s the rate at which Oxygen is absorbed by the body for use in muscle contraction and life-sustaining activities. The Greeks believed that breath was life… and they were right.

The Vo2Master Provides a TON of information!

Vo2Master App Metrics
This is just one page of data fields that I can use on the Vo2Master app. You can also run these fields as graphs. All of the data is stored in a detailed .csv file that can be downloaded and shared for analysis.

Since it launched over 5 years ago, the Vo2Master app continues to improve. Just about any sports fitness product that has Bluetooth transmission can now be recorded. These myriad data points can also be displayed, in numeric or graphical format. My only complaint about this has been the inability to display and record this information on a larger screen, like that found in a laboratory or on a regular PC. But that’s a side project that I’m actually working on via (fitnesshrv.com). The app can also be simulcast from a phone or tablet to a large screen with 3rd party apps or with Apple TV.

For this test, I recorded the following external data points:

  • Load Generator (Ergometer)
  • Power (crank)
  • Heart Rate (chest strap)
  • Heart Rate Variability (HRV)
  • Cadence (crank)
  • SmO2 (Moxy)

These data points allow me to transfer the information learned in from the Vo2Master, over to my body and bike when I’m cycling outdoors.

For the ‘Native’ Vo2Master data, I recorded:

  • Respiratory Frequency
  • Tidal Volume
  • Ventilatory Exhalation in Liters per Minute
  • Expired Oxygen

ALL of this information was recorded on a single .csv file, and a summary report was delivered after the test ended.

Any information that was able to be transmitted via Ant+ signal, was also recorded on my Garmin Head Unit.

Vo2Max Test Parameters

I can build just about any test protocol I wish to construct, but the most common Graded Exercise Tests for Vo2Max are built like this:

  • A decent warmup that includes instrument and ergometer calibration to ensure accuracy.
  • 2-4 minute stages at preset wattage loads.
  • A 25 to 30-watt jump (“step”) at the end of each stage.
Vo2Master Graded Exercise Test App Protocol
The Vo2Master app can perform Graded Exercise Tests, ‘5-1-5’ type tests, and even training intervals. Variations within each set are based on time and intensity.

For this test, I had already warmed up, so I just chose a 5-minute warmup, 3-minute stages, and a 30-watt jump in each step.

The Test

Vo2Master Graded Exercise Test
The area in grey is the exercise load. Purple is the power coming off of my power meter on my bike. Red is my traditional heart rate. Blue is the Vo2 data coming from the Vo2Master.

The test was performed on July 14th of 2024. The previous week, Garmin Connect had my Vo2Max calculated at 57ml/kg/min. The Primary goal was to determine the accuracy of this number. The secondary goal was to determine Ventilatory Threshold #1 (VT1) and Ventilatory Threshold #2 (VT2) to see if those wattage, heart rate, and other physiological results, were in-line with the Calculations made by Garmin Connect.

*** Remember – this is just ONE individual performing ONE Graded Exercise Test. There’s nothing linear or broad. I’ll add to this information over time, but it’s just a snapshot of my fitness, compared to a mathematical algorithm by a fitness company.

I began the test at 100 watts of resistance, which was then raised by 30 watts every 3 minutes. I ended the test at roughly 300 watts of ergometer load, when I was exhausted, and my Max Heart Rate was at a value I hadn’t seen in about 6 months.

A Few Problems with the Data

When you look at the graphs I’m providing, you’ll see that there are two problems with the data, neither of which is enough to discount the information in it, but it IS important to understand the results.

Vo2master test anomalies
I’ll perform this test again some time, using an axle or spider based power meter. I may also acquire the ‘other half’ of the power meter (the left leg – this is a rare, right-leg-only pm), and show why 2-legged pm’s are so much better.

First – there’s a glaring delta between the Ergometer Load and the Power generated. Those two values should be roughly 1:1 (Power should be roughly equal to the resistance provided, per Newton’s Third Law). The Power lagged behind the Ergometer load the entire ride, even after calibrating both devices. I believe the data from the power meter is accurate, however, and it’s the information I would use outdoors or in training. So, while it’s not in line with load, it does still provide valid data.

Second – the power line itself is variable. I blame this on the fact that I use a one-legged power meter indoors, and the data packets can ‘speed up’ or ‘fall behind’ at certain cadences. I’m fully aware of the shortcomings of one-legged powermeters, which is why, when I ride outdoors, I truly prefer axle-based powermeters, and more specifically, ‘two-legged’ power meters that trap the torque on both cranks, and use the information to compute a more accurate and thorough set of data.

For this test, the average for each step was fine, but in the future, I will make two specific changes. I’m going to purchase a more modern trainer, and I’ll purchase the ‘other leg’ of my power meter, so I can get the more accurate information for my indoor-only bike.

Vo2Max Results

The most important question I wanted to know was what the Vo2Master would show my Vo2Max to be, and what that value was in relation to the calculated estimation of Vo2Max from Garmin Connect.

Here are the results:

Vo2master Vo2max Graded Exercise Test Report Results
This is the first page of the Graded Exercise Test Report from Vo2Master. I basically blew a 56 Vo2, which lines up with the calculation that my Garmin Connect has made, at 57 just a week before.

The Vo2Master trapped my Vo2Max at 55.8 milliliters of oxygen consumed per kilogram of body weight per minute of exertion.

Garmin Connect had recorded a 57 about a week earlier. That’s 98% consistent.

I’ll Take it.

Other Fitness Data Points

If you know anything about me, you know I’m a nerd for Data. The goal for me as a Coach, however, is to help ‘distill’ this information in to practical knowledge. That’s why I focus on lower-cost alternatives and Garmin Connect, to set fitness levels, training zones, and fitness programs. Progression does require frequent re-assessment, however, which is why I like using the Vo2Master. It provides the ultimate, scientifically validated information that we can then use to reset these zones with more accuracy.

Vo2master Heart Rate Vs Wattage Graph with VT1 and VT2
The linear plot between heart rate and wattage is nice, but it’s even better when you plot VT1 and VT2 against the other two metrics. This gives you the knowledge to understand just how ‘hard’ you can ride before physiological and metabolic changes in energy consumption start to occur.

Ventilatory Threshold 1 (VT1)

Ventilatory Threshold 1 (VT1) is a point in time where the Respiratory Rate (RR) or Ventilatory Exhalation (VE) in Liters per Minute, outpaces the rise in Vo2. It is ROUGHLY analogous to Lactate Deflection Point #1, which is an invasive measurement that uses needles and blood to assess the processing of lactate as energy. When that value rises, exercise physiology changes energy use from mostly fat consumption – to fat and carbs consumption, to overwhelmingly carb use for energy. Lactate testing is invasive, adds risk, and the data collection is prone to error. As a result, I use Saturated Muscle Oxygen from a Moxy, and I also use DFAA-1, a measurement that looks at Heart Rate Variability, to assess these intensities, when I’m not wearing a Vo2Master.

Vo2master Gas Exchange FeO2 and EqO2
While I’m not discussing this chart in this blog, the information it’s providing is priceless. FeO2 is expired oxygen. If less o2 is exhaled, that means more is in the bloodstream and is helping the muscles with contraction. It shows the ‘Air’ in ‘Aerobic’ Exercise!

The Garmin Connect system, paired with Garmin bike computers and watches, uses power, heart rate, heart rate variability, respiratory rate from the chest strap, and weather information, to come up with heart rate and wattage zones. These values CHANGE with changes in volume and intensity over time, which is one more reason why I’m intrigued with what the Vo2Master has to say, in relation to the zones set by Garmin Connect.

Garmin Connect Algorithm Vs. Vo2Master Gas Exchange Results

Vo2master with Tidal Volume Ventilatory Exhalation and Respiratory Frequency
Here’s another Graph of the Vo2Master data plot. My Tidal Volume, at 3.7 liters, is actually a bit low; I need to train for deeper, slower breathing. This will delay the onset of VT1 and VT2, and thus improve my economy.

Here’s the comparison between the Vo2Master Zones, and the Garmin Zones after the test.

VT1/Zone 2 ‘Fat Burning’ Zone…

  • Vo2Master: 142 Beats Per Minute for VT1. Below that value, let’s call it ‘Zone 2’
  • Garmin Connect: 145 Beats Per Minute.
  • That’s a 2% difference.
  • VT1 Wattage Value? 183 watts
  • Zone 2 Upper Value for Garmin Connect: 179 watts.
  • That’s a 2% difference…

VT2/Functional Threshold Heart Rate and Power…

  • Vo2Master: 174 Beats per Minute. This is the ‘zone’ above which you’re on borrowed time, and below which, you can still exercise for an extended duration.
  • Garmin Connect? 172 Beats per Minute.
  • 1% delta. Again – I’ll take it.
  • Vo2Master Wattage at VT2/Threshold? 251 Watts.
  • Garmin Connect? 247 Watts.
  • A 1.5% delta. Again – for fitness purposes, I’ll take it.

Setting SmO2 Zones Based on Vo2Master Data

Once the VT1 and VT2 Values for wattage and traditional heart rate were set, I then took a look at the Saturated Muscle Oxygen information at those breakpoints.

Vo2master With SmO2 and ThB Values from a moxy monitor
I love, love, love my Moxy Monitors. They offer a noninvasive way to measure intensity on the ‘demand’ side, while heart rate provides information on the ‘supply’ side. Note the inclusion of Total Hemoglobin, or ThB. Thb declines until I reach VT1, then plateaus in my ‘tempo zone’, then begins to rise as I surpass Functional Threshold Power, or VT2.

Here’s what it showed:

  • SmO2 at VT1, where heart rate was 142 bpm and wattage was 183 watts, showed 37% saturation on my Left Lateralis. I usually use 40% saturation as my VT1/LT1/Zone2 breakpoint, so this value is in sync with my perception.
  • SmO2 at VT2, where heart rate was 174 and wattage was at 251 watts, was at 19% SmO2 Saturation. Again – I tend to use 20% saturation as the mark for my VT2/LT2/Threshold.
  • SmO2 measured by a Moxy on my Left Lateralis, showed highly correlated values with VT1 and VT2 for wattage and heart rate. That’s now three datapoints I can use when training, indoors and out, to correlate with the Gold Standard of Gas Exchange Analysis.

There are some great studies which show how SmO2 is equally valid to Lactate testing. The advantage is that SmO2 is noninvasive. I use SmO2 daily, and rely on it for optimal warmup and vasodilation, as well as for monitoring hydration and even looking at Moxy highs and lows during intervals, to gauge exhaustion more accurately. Most of you reading this already have a Garmin watch or bike computer and an advanced chest strap. Investing in a Moxy can augment your knowledge and improve upon your intuition about intensities and the duration you can ride at those levels.

Conclusion

Vo2Master GXT Zone Prescription
I usually simplify the 5 zones to just 3. Stay below 142 for base, stay above 174 for Vo2Max intensity, and work intervals above and below 251 and 183 watts (these will change with fitness).

The Vo2Master’s Vo2Max readings confirmed the calculations I am getting from Garmin Connect. Correlation between Vo2Master’s VT1 and VT2 for wattage, heart rate, and Saturated muscle oxygen, was also high.

The Vo2Master is the pinnacle of portable, accurate, physiological testing. I’ll be using it on some outdoor rides on the mountain bike to show just how hard mountain biking is, and how we can use that information to better train and prepare. Perhaps more importantly, at least in my case, the Vo2Max calculated through Garmin Connect, along with the thresholds and zones, means that I can train with higher confidence, knowing that the physiological data backs up Garmin’s claims and assumptions to a really high degree!

Thanks for reading, and #EnjoyTheRide!