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Heat Adjusted VO2Max?

badbri
over 5 years ago

This might be a question for HermanB but maybe someone else knows.

Does the recorded ambient temperature affect the VO2Max score the 945 measures?  I'm in the American south and we are starting to finally get some good does of particularly hot/humid conditions.  And I have noticed my VO2Max number ever so slightly dropping after some of my particularly hot runs.  I would hope that it would be accounted for but maybe it's not quite that sophisticated?

  • 0 over 5 years ago

    Garmin will tell you so. I mean, the heat acclimation in principle is design for that. Once you get 100% acclimation the watch will take it into account for VO2max and training status. However, in my experience, it does nothing. Past summer I had same VO2max drop despite being 100% acclimated than I experienced one year before with the FR935. So, as far as I can tell, it doesn't work. But maybe it was just me. 

  • 0 over 5 years ago

    Temperature needs to be above 22C and from a weather service via a phone, maybe a Tempe sensor. The temperature you see on the watch is not used.

  • 0 over 5 years ago

    I agree I don't think it's accounting for it.  I do get heat acclimation numbers rising (I'm up around 47% now) but VO2Max has been steadily decaying for about 2 weeks, which is roughly when the heat/humidity around here has started to steadily kick in.

  • 0 over 5 years ago in reply to Dr Phil

    I have a Tempe but I've been told that only weather service recordings are taken into account.  So you must sync your 945 to the phone app at least within 2 hours of the run for heat acclimation to have an impact.  But I don't know about Vo2Max.

  • 0 over 5 years ago

    It is the FORECAST temperature (from the weather widget) that it considers, not the recorded temperature. 

    Certainly VO2Max is less temperature sensitive than my Fenix 5, where the VO2Max would plummet as soon as I did a hot run. But it can still dip.

  • 0 over 5 years ago in reply to mcalista

    I see the same. The more my FR945 thinks I've adjusted to heat, the less the drop is. I'm not quite sure what algorithm it used, but acclimatisation is calculated based on temperatures above 22C. There is a big different in how the body reacts at temperatures of 24C compared to, let's say, 35C. 

    The watch is only able to give an indication, which is based on a number of variables that it measures/collects. There are also variables that the watch isn't aware of, like terrain. Running on asphalt usually has a positive effect on VO2Max calculations, where sandy forest paths have a negative effect, because the body simply has to work harder to maintain the same pace.

    Although I'm positively surprised with the VO2Max that my FR945 calculates, if you want to know your true VO2Max, it's best to get that measured in a sport medical test.

  • 0 over 5 years ago in reply to eberends
    eberends said:
    Running on asphalt usually has a positive effect on VO2Max calculations, where sandy forest paths have a negative effect, because the body simply has to work harder to maintain the same pace.

    That is precisely why there is a "Trail Run" activity, which does not affect VO2Max (but is still included in Training Load and Heat Acclimation).

  • 0 over 5 years ago in reply to eberends
    eberends said:
    Although I'm positively surprised with the VO2Max that my FR945 calculates, if you want to know your true VO2Max, it's best to get that measured in a sport medical test.

    Oh I don't really follow the number "absolutely" but instead "relatively."  If the number goes up then I feel like my training is working.  Similarly if it stagnates, or goes down, then i wonder what is up.  Could be training or illness or some other factor.

    I only run roads twice a week at most, and on roughly the same courses so it's a decent comparison over time.