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VO2 max calculation: Have HRmax be an input field if known

The white paper for VO2 max 

 https://assets.firstbeat.com/firstbeat/uploads/2017/06/white_paper_VO2max_30.6.2017.pdf  states Firstbeat calculates VO2 max using an age-based estimated max HR. It also documents error in calculated VO2 max if the HR max is inaccurate - up to 9% error in calculate VO2 max for a 15 BPM error in HR max.


Perhaps Firstbeat could consider making the HR max an input field if it is known, to remove that potential contribution to overall error of VO2 max calculations?


Thank you!


Hi Alexis!

Thanks for your question about the VO2max estimation and maxHR. 


The maximum heart rate value can be input to all the Firstbeat programs and also to most of the consumer devices utilizing the VO2max estimation analysis. In the Firstbeat Lifestyle Assessment software, the specialist making the analysis is able to input a new maximum heart rate if this is known, and thus calculate the possible VO2max estimation with the new values. 


In the Sports products both the coach and the athlete are able to enter maximum heart rate values to the athlete profile information. 


Which Firstbeat product are you using? Perhaps I could help you enter your correct maximum heart rate to the device/software to get the most accurate VO2max estimation.

Hi Nelli - Thank you so much for your kind response!


I am using the Garmin Fenix 5S Plus. I have manually entered a HRmax value there, determined during peak exercise (it was 16 BPM higher than the 220-age formula result). I didn't realize from reading FirstBeat's white paper that FirstBeat would use that manually-entered HRmax value for the VO2max calculations, that is wonderful!


Spiros had also sent me a response, and I replied to that before I saw your kind response. I don't want to use up your resources unnecessarily by speaking to two engineers! … but I had another question that I forgot to ask him a few minutes ago. May I ask you, and if you like you could answer, or to save your time pass it along to him?


  -- Knowing from the graph in your VO2max white paper that any given VO2max calculation is within 5% of the true VO2max … would you know if intrasubject sequential VO2max calculation results are all equally off by the same magnitude and direction? 


If so, then it might seem that trending VO2max is valid to follow training effect. But if any given VO2 max could be 5% too high or 5% too low in sequential intrasubject testing, then it may be more difficult to understand changes in fitness over time by referencing sequential VO2max values, perhaps. 


Thanks for your help in understanding this wonderful science you folks have put together!


(After this I will similarly be trying to understand lactate threshold better, especially the validity of trending it to use it as a surrogate of improving (hopefully!) fitness over time).


Thank you again, Nelli!

Hi Alexis!


Thanks for you question. 


The MAPE (Mean Absolute Percentage Error) is about the 5% in each test. This is a very low error percentage as you can see from the White paper: the laboratory tests show a similar error (5%). The results should be as accurate as possible as long as you have the background information up-to-date at all times.


I hope this was helpful. If you have follow-up questions, don't hesitate to email us!

OK, thank you, Nelli!


Best regards,


Alexis