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High aerobics stuck at zero?

Steve
over 5 years ago

Hi, since returning my FR945 and switching to a Fenix 6S Pro 4 weeks ago, my Load Focus still says zero in the midrange (all of it goes to low aerobic, plus a little to anaerobic). I don't run or bike--only do hiking of increasing intensity. But on the 945 the same routes got me into optimal ranges on all 3 (low, high, anaerobic). Since i don't get some of the other feedback runners do, this was a valuable metric. Any ideas? Thanks.

  • Former Member
    0 Former Member over 5 years ago

    If your not hitting zone 5 then you are not going to get anaerobic numbers. Zone 4 should give you high aerobic numbers.

  • 0 over 5 years ago in reply to Former Member

    That's the thing: I AM collecting anaerobic numbers, while high aerobic stays at zero and low aerobic is through the roof. Thx.

  • Former Member
    0 Former Member over 5 years ago in reply to Former Member

    You can absolutely get anaerobic load and training effect without hitting zone 5 (assuming zones 50-60-70-80-90% of HR max). You get anaerobic effect by rapid shifts in heart rate, for example from zone 2 to 4 (or 5, but not necessarily), as when you do repeated short intervals, with sufficient rest  between repeats. You can in a similar way get high aerobic load by maintaining a session in high zone 3 (just below threshold). I did today, during 90 minute session, of which 70+ minutes in high z3, just below my first threshold heartrate. I also regularly get anaerobic effects from intervals without hitting much time in z5. Just as expected.

    Zones are individual. You set them yourself, or accept the suggested zones by your device. Zones are also depending upon you knowing fairly well your max hr or your threshold hr. I use the latter as a basis for my zones. My HR levels are tested in a lab, so I consider them trustworthy. I do not use the age formula. To my understanding, the Firstbeat algorithms in the Garmin devices do not depend upon zones for their calculations. I believe there is a good white paper on this at www.firstbeat.com.

    To the OP make sure that your HR max is set correctly (or same as on your earlier 945). When it comes to hiking, it is very hard to push yourself into high aerobic loads, unless you do quite massive altitude gains or do speed hiking (more like trail running). I never get high aerobic or anaerobic loads on hikes, with speed hiking/trail running sessions in the alps as the exception. For me, a HR strap is also necessary to get trustworthy hr measurements. I did a couple of sessions last year in the alps, relying on the optical wrist hr sensor in my Fenix 5, and it gave me much too high hr measurements, and therefore also faulty (too high) load and training effect. This season I have made sure to use a HR strap for hikes/speed hikes that I consider as training sessions. If you get anaerobic loads, as well as low aerobic loads, it sounds like you get a lot of time in the lower heart rate zones, in combination with shorter bursts of rapid increases in heart rate. As you may get if there are plenty of altitude variation, and you increase your efforts as you gain altitude. Continuous long climbs with a high level of effort should lead to a higher aerobic load.

  • 0 over 5 years ago in reply to Former Member

    nquand, Thanks for the thoughts. Since my zones are basically the same as when i had the 945, I just want to narrow down whether the readings are a) maybe my heart rate is lower on the same routes due to conditioning, b) maybe the Fenix 6pro algorithms are different, or c) I'm just really good identifying Garmin bugs. Will keep testing...