Revvo: Inexpensive VO2Max (Fitness) Testing in SF

Hi Everyone, I wanted to introduce you to Revvo, a smart exercise bike that accurately measures VO2max without using face masks - thereby making this simpler, less expensive and perhaps even a bit of fun!

VO2Max (aerobic capacity) is the max oxygen the body can uptake and perhaps the best indicator of fitness and health. But very few people measure this today since its an expensive test ($150 in a lab) and you have to wear a face mask (which can be difficult to breathe through).

So Revvo started as a DIY project as I was struggling to improve my fitness & health (despite exercising pretty regularly) and wanted a fitness benchmark that I could use to experiment against. I shared some of my early learning at a QS session in Boston in 2014 (

This is now a fully functional product and we’re seeing pretty strong accuracy in our testing against gold standard lab benchmarks.

We’re doing a special 2 tests for 1 promotion until May 15, 2016 (you need to get your first test in by then), which can be particularly useful for those of you running experiments that could potentially affect any aspect of your fitness & health.

Schedule your test via
(San Francisco only for now)

Hope to see you all there!


Looks interesting, and most likely a very good method to estimate VO2max as power and submaximal HR are very strong predictors of aerobic capacity.

My only comment is on terminology :slight_smile: By definition you are not measuring oxygen consumption, and therefore I would not claim that you measure VO2max without face masks (as the only way to do that is in a room calorimeter), but you estimate VO2max…

Good luck with your work, as I’ve done some research on estimating VO2max in free living during my PhD, it is great to see more of this stuff, and hopefully we will slowly start including these “proxies to health/cardiovascular fitness” more often among the parameters that we can track easily, potentially closing the feedback loop between our physical activity behavior (steps, runs, energy expenditure, etc.) and the effect of our behavior on our health status.

1 Like

Hi Marco - thanks for the response and yes agree with you that there is clear opportunity to use metrics like VO2Max to evaluate the effect of behavioral intervention on overall fitness / health.

On whether we should say estimate or measure – its a really good question. Reality is that respiratory gas exchange is also an estimation - it measures VO2 and VO2peak but you don’t really know if it measured VO2Max. In our case, we don’t measure VO2, but we do directly measure VO2 driven output (i.e. no prediction or extrapolation involved - its a max test, not a sub max test, this is not based on assumptions about max HR etc.). So for now – we’re staying with measure as a way to better describe exactly what we do & differentiate from the many prediction and extrapolation methods that exist – but yeah this is something I continue to evaluate regularly.

1 Like

The Precor machines at my gym have a “fitness test” mode that estimates your VO2max from power output and heart rate. How does Revvo improve on this?

1 Like

There’s actually quite a range of fitness equipment that estimate VO2Max based on your output with or without heart rate (including Garmin, Microsoft Band etc.). Most (though not all) calculate your max heart rate from a formula and then estimate your VO2Max from a sub max protocol. Max HR can vary quite a bit (+/- 15-20 bpm) from that predicted by the formula – so you have three levels of variation - sub max protocol, max HR assumptions and then the prediction equation (which is usually built on previous datasets).

We don’t make any of the above assumptions – our protocol guides you to your max power output (so its a true max test, where we elicit a max HR response that’s usually the same as a real VO2Max test) and then we use the heart rate data to figure out how much of that max aerobic output is aerobic versus anaerobic. So its a very different approach from conventional and therefore gets us much closer to lab accuracy across a very wide range of subjects (at least in our initial results – more work to do of course!).

You should drop in to test – that’s the best way to learn :slight_smile:

I’m guessing there are liability issues with doing true max heart rate tests? In any case, I’ll check it out Revvo next time I’m in SF!

Partly that – if you get someone with a cardiac history then unless a physician is present you’ll have to route through a sub-max - so precor may be defaulting to sub-max for everyone. But also because the conventional max test is actually difficult even for well trained athletes – even in a lab test you can get significant variation in VO2Max if you don’t actually get that person to their ‘true max’.

We use a different protocol that was designed from the ground up to be both doable yet effective in eliciting a max output.

Dear @Siva_Raj,
@Marco_Altini gently asked his question, but now I will boldly suggest that you are baiting to offer “VO2max testing”, switching that (in your head) with “Aerobic Capacity” testing, and then hiding post-after-post exactly what is supposedly measured. Surely there is a senior at Revvo that can help you handle this critique?

Your response shows either naïveté or purposeful spin, the latter not tolerated in this community!
“Reality is” that respiratory gas exchange measures oxygen consumption (period). Whether the maximum value measured is 95, 98, or 99.5% of the individual’s “true instantaneous max” is one of the things about “Reality” – you’re never quite perfect, but we can get together in the spirit of HONESTY and FORTH-RIGHT sharing to compare and validate reproducibility & trueness.

Again: “What is RevvO measuring?”

Responses not accepted:

  1. “You should drop in to find out. I don’t know what’s measured.”
  2. “You should drop in to find out. That’s the only way I can trick people.”

Hi Jackemeyer - I’m pretty sure we have a long way to go before we get really good at explaining our methods and how they are different from respiratory gas exchange et al (and I wish there was someone else I could lean on but since I invented the tech, I have the job of clarifying it).

However that doesn’t mean you can shout out wild accusations based on conjecture about our motives or self appoint yourself as the spokesperson of the QS community - this product has been built with the help from members of this community both in SF & Boston. And I’ve personally shared our journey from Day 1 in multiple QS forums - not usually the sign of someone trying to hide stuff.

Now to answer your question on what is Revvo measuring, as I ran through in my earlier responses (and now breaking this down further) :
1/ We measure cycling power and heart rate.
2/ We run a VO2Max test
3/ At the end of the test we measure max power
4/ We use the heart rate data to figure out how much of that max output is aerobic versus anaerobic.
5/ The max aerobic output is converted to VO2 units = VO2Max

There is in general a very tight relationship between VO2 (oxygen consumed) and energy produced (work rate). Measuring max power gives us a direct measure of max work rate and by implication max VO2. The challenge is that not all work you do is aerobic (i.e. oxygen inducted) – some of it is anaerobic (i.e. does not use oxygen) and the anaerobic component increases at higher intensities. So that’s what our methods do - they figure out the aerobic component of the max power output so we can compute max VO2.

Now should we call this measurement or estimation – as I mentioned in my original response, we’re still debating that. As I also pointed out our methods are very different from any of the other estimation methods that exist today, so yes I expect we will continue to work on clarifying our approach.

And to use a different analogy: is the apple watch measuring heart rate or measuring pulse rate ? Should only methods that use a 12-point EKG say that they measure heart rate – I’m pretty sure we can similarly debate that for a long time to come.

Glad for the answers:
Duration: a predefined time or to fatigue
Measured: angular velocity & torque using a dyno, and data from an individual’s pulse using ECG or PPG.

No need for analogies. The problems with your wording is now clear.

Glad you found it helpful. The problem with your wording is however not resolved - I’d like to see an apology first