Fitness "contradiction"?

Hi, would get some views/opinions on my thoughts here, or maybe I’m totally wrong about this all together.

Some background.
I’m +52yrs old, run every second day (mainly sub 1 hour), ride bike every second day (mainly sub 1h20min)and do strength training almost every day (push/pull/legs). No elite ambissions or competing in races etc. Just wanna see how fit/well trained I can get this old grumpy body.

I use Polar Vantage V2 and Polar Flow to monitor my cardio strain, load and tolerance, recovery, VO2max, HRV etc

I’m at VO2max 53 and my cardio tolerance is 109 (according to Polar)

I read alot and watch YT alot for subjects related to training/healthy food etc.

Everywhere I read 80/20, slow to get faster, more low intense to increase fitness etc. After low intense sessions Polar summary says things like “good steady low intense training, improving your fitness and your body performance bla bla bla”

If this is true, I would expect to see improved cardio tolerance value or VO2max or just anything indicating that my fitness benefits from the low intense/slow/recovery.

Instead I just see a decline in my cardio tolerance value. This leads me to the conclusion that the only way for me to increase my cardio tolerance value is to constantly train harder to generate more cardio stress (28 days avg) which totally contradicts all I read about training volume in low intense/slow training. So if I want to max my cardio tolerance value, I should go bananas for 28 days straight and reach an unsustainable cardio tolerance value and then try to stay at that level. Doesnt at all feel like the recommendations i read about enhancing fitness.

I like numbers, gadgets, statistics, graphs etc. If its not a number, it doesnt exist :grin:

Maybe it is just Polar cardio tolerance value that I misinterpret as “fitness” (maybe its the name that is just misleading?). Is there any other value that can be easy to measure/monitor?

I really don’t like to get punished after low intense/slow sessions by reduced cardio tolerance value. Its hard as it is already for me to do those sessions in the first place.

A lot of bla bla bla but it has been bugging me for weeks.
I guess I had to get this out of my system :rofl:

I can recommend


I would honestly not put too much empahsis on arbitrary numbers generated by algorithms on fitness apps and instead measure fitness gains the good old fashioned way - real-life performance.

Best simple ways to measure fitness gains in cycling are either i) FTP test or ii) 10mile TT time.

Do one of those once or twice a month and ur good to go. Track it over time and see how it changes!

p.s. you say you are running, cycling, & doing strength work, seemingly every day. Do you factor in any rest days? If you are able to work out every day, then maybe your workouts are not high enough intensity…! Also, at 50+ yrs of age, main goal is maintenance rather than big gainz I am afraid…! But still very very good for your long term health to continue exercising (especially strength work, as muscle decline increases with age but this can be slowed). :+1:


I don’t know the Polar algorithm but if it’s anything like the Strava fitness algorithm (and given Polar are likely to go heavy on HR analysis in their algorithm given their core business I’m guessing it is) it’s a) not really important and b) going to decline if you get fitter but don’t increase your load (which if you keep the intensities the same means varying the volume).

i.e. I’m a lot fitter than last year. If I ride for the same time at the same intensity as I did a year ago I’ll get a lower relative effort. That lower relative effort will result in a lower cumulative score in the fitness graph, but I’m fitter, a lot fitter, measurably so by other metrics like FTP, and most of it was achieved in a higher volume, low intensity base season Oct-Dec. Which leads back to the start, don’t put to much importance in it going up to measure your fitness. What it’s really telling you is you are ‘neglecting’ an opportunity you’ve built up to train harder/longer. Given all the evidence you can’t train harder and harder and harder, that does lead you to training longer (or sweet spot if you buy into that). That’s why I’m up to 12 hours a week from the 9 I was doing before. You can make it go up but it’s a vicious circle if you don’t want it to take over your time.

If you want a daily fitness tracker then I find Xert’s FTP tracking (which doesn’t need FTP tests to work) better. Not perfect, but much better

Dr Dean Ornish. Check him out

A bit slow to reply but here’s my view on it (I’m also a Polar user).

I find the Cardio Load Tolerance to very well estimate my fitness. It correlates well to my FTP in that the higher the Tolerance the higher my FTP (in general).

You mentioned that the only way to raise the Tolerance is to train harder. This isn’t true. In my experience the best way to raise it is too train longer, not harder. An absolute smashfest 40 minute interval session may only yield a 2/5 Cardio Load, but an easy 3 hour ride gives 4 or 5/5. The latter ride is much easier!!

So I suggest trying longer easy rides, it’ll likely increase your Tolerance more and is more sustainable than riding hard all the time. Sustainability and consistency is the key. Just don’t expect your Tolerance and fitness to keep going up forever! Wouldn’t that be great.

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Hi Dan, I got response from Polar that the Cardio Tolerance is a formula based on HR and Time as biggest influence. So either light and long or Intense but shorter. When I train intense, typically 60-80 min my tolerance goes up rather quick but then when I move into lighter training periods it drops quite fast. Only way for me to not drop fast during low intense is to increase my typical time with at least x2.
I typically gym 6-7 days a week and run every 2nd day and bike every 2nd day and my Max Cardio Tolerance I managed to achieve is 123. My Intense trainings are mainly Z4-Z5 and Low intense is low Z3.

These days I pay less attention to strain, tolerance and load. More use it as an indicator if I am too much in the danger zone :slight_smile:

Been looking at many YT videos about how fast fitness/tolerance declines if you don’t train for a week or two and they say almost no decline within a week and a little bit if more than a week. According to Polar, 1 week of no training my tolerance number would get a huge dip south.

I just have to learn to accept the algorithm :slight_smile: