What We Learnt from 750 Fitness Tests!


Weight is a very poor proxy for fitness (even though culturally we think fitness = “being in shape”). Increasing activity improves fitness but does not lead to lower weight. Fitness declines with age, but this is not a given. Improving recovery is an ‘easy’ win for everyone.


Revvo is the first exercise bike to measure an individual’s fitness profile : Aerobic Fitness/VO2Max, Recovery and Endurance/Threshold. And right from the earliest test, we’ve captured information on the individual’s demographics and current weight, activity levels (mainly because it was required pre-screening information).

1. Test Fitness

While we’re definitely not the first to aim to understand how these different variables correlate, the fact that we are measuring a wider range of variables on the same individuals with a pretty high degree of accuracy and consistency should hopefully provide some additional insight. Details on the test methodology can be found here: Revvo: Science.

1. We tested people across a wide range of fitness levels

While our sample is not a fully representative one (we do not have many at the lowest and highest ends of the fitness spectrum), it does represent a broad spectrum of fitness levels – both in terms of VO2Max and Recovery.


Interestingly, Recovery is skewed lower than the VO2Max results and this is something that we’ve anecdotally observed in quite a few “fit” individuals. Recovery is partly an indicator of lifestyle – stress, lack of sleep will show up here. So if you’re looking to enhance performance or general wellness, check your heart rate recovery status — sleeping better and reducing stress might give you immediate results.

2. If you’re already fit, focus on recovery

In fact this opportunity to improve Recovery becomes more obvious when you cross-analyze VO2Max and Recovery data. In general, there is a positive correlation between the two i.e. higher the VO2Max, higher the expected Recovery. However this is a weak correlation as you’ll see from the plot.

Vo2Max Vs. Recovery.png

I’ve often seen people with relatively poor VO2Max scores who’re doing fine from a health perspective since their heart rate recovery is good and also fit people with poor recovery that indicates underlying health issues (perhaps genetics the culprit here rather than lifestyle). Fit people also often have poor recovery due to excessive training loads i.e. if you ran an ultra-marathon over the weekend, it will take a few days for recovery to return to normal levels.

3. You could be fat & fit or thin & unfit

We often conflate weight and fitness – but these are two semi-independent variables. We’re seeing lots of people who are relatively heavy but score pretty well on VO2Max (despite the fact that weight is the denominator in VO2Max calculations). And on the other hand many who have perfect BMI but with suffer from aerobic fitness.

VO2Max Vs. Weight.png

Above 250lbs however, its rare to find someone who’s really fit. But below 200lbs there’s a huge variation in fitness levels – if we only analyzed that population there would be very little correlation between fitness and body weight. So just because some looks thin doesn’t mean they are fit and vice versa.

Recovery versus body weight shows the exact same pattern.

Recovery Vs. Weight

4. Being active improves fitness, but doesn’t impact body weight

We’ve now seen a ton of data confirming that activity, on its own, doesn’t seem to make much difference to body weight. And our analysis supports that conclusion.

There’s practically zero correlation between how active people say they are and how much they weigh and a slight negative correlation when you contrast BMI vs. Activity. Yet we keep telling people that they should exercise more to lose weight, setting them up for failure!

Body Weight Vs. Activity

BMI Vs. Activity Level

Why does increasing activity levels not help with weight loss? Vox did a fantastic summary of the available evidence in this video and article.

The real benefit of activity is an improvement in fitness – and this is what our analysis reveals as well. Higher activity levels correlate pretty well with higher levels of fitness.

And aerobic fitness (VO2Max), as I’ve explained before, is not just an indicator of athletic potential but also the single best overall indicator of health. The primary purpose of exercise is to improve the functioning of your heart and muscle. Weight loss, if it happens, is a spin-off benefit.

Therefore if you want to assess if exercise is yielding results, track your fitness level, not your body weight.

VO2Max Vs. Activity

This is not of course not a perfect correlation as different types of activities have different effects: walking for an hour will not improve VO2Max as much as 10 minutes of high intensity interval training. And genetics also effects how well activity translates into an improvement. Which is why, even for people at the same level of activity, there is such a wide variation in fitness levels.

The correlation between Recovery and Activity is not as strong – and this makes sense. Lifestyle factors (sleep, stress etc.) often have a bigger effect on improving Recovery than increasing activity per se. And of course being too active can negatively impact Recovery. Recovery is intrinsically a more complex variable.

Recovery Vs. Activity

5. Fitness can – but need not – decline with age

At a general population level, VO2Max is reckoned to decline ~1% per year as we age and our analyses confirms the broad trend. However within that trend, there is huge variation: we’ve seen so many young people who are less fit than their grandparents and so many older individuals who’s fitness level has been an inspiration to me personally.

So your fitness is in your hands (or legs!).

VO2Max Vs. Age

Recovery seems to be even less correlated with declining age.

Recovery Vs. Age