Establishing AeT

  • Creator
  • #40646
    Matt L.

    I’ve recently started using a Garmin chest strap to monitor my HR, and am making a real effort to establish an AeT after using the wrist-based monitor to guesstimate it.

    I have two recent runs, both long and at a pace that felt easy. Course is almost identical. The difference in mileage accounted for by adding a few extra loops on flat city streets. Area is mostly flat with a few short easy grades.

    Both runs are under 5% on TP pa:hr. (Free, so I’m not able to use the aerobic decoupling feature to eliminate warmup HR)

    Run A:
    Time – 1:27:40
    Distance – 9.8 mi
    Avg pace – 8:57/m
    Avg HR – 171 BPM
    pa:hr – 4.73%
    Temp 79-88 F

    Run B:
    Time – 1:16:11
    Distance – 7.8 mi
    Avg pace – 9:44/m
    Avg HR – 154 BPM
    pa:hr – 0.38%
    Temp 69-81 F

    My question is, which of these runs is more representative of my AeT pace and AeT HR, respectively? Run A was hot and humid, and I felt myself really cutting back my effort to keep my HR low in the heat.

    Is there any meaningful data to be drawn from these two, or is the answer to just do another long run under cooler conditions?

    Background- 29 y/o m with a 7 year history of physical, low intensity but long duration forestry work. The work incorporated lots of hiking under a load. I began training seriously about 2 years ago and am coming off a three month break in training. My training hours over the past 2 years are 3-6 hrs/ week, but there’s a lot of uncaptured ‘training’ hiding in there because of my work.

    The past three months I’ve been behind a desk, and so no hidden hours there- big ole 0.

  • Participant
    OwenFW on #40653

    Why don’t you warm up for 20 min before starting your run on the watch?

    Matt L. on #40663

    I’ve got to admit I wasn’t terribly worried about that issue particularly. Wouldn’t the first few miles skew the pa:hr higher and lead to a more conservative number?

    That’s definitely a good way to address the warmup numbers if they’re generating bad data.

    Anonymous on #40851

    These sessions are hard to compare because of the heat/humidity and the difference in HR.

    It’s important to note that when finding AeT, HR will drift less than 5%, but it could drift higher with higher intensity. Basically, doesn’t drift higher but it could. In contrast to AeT HR, AnT HR doesn’t drift higher because it can’t.

    You’ll want to test in similar conditions to make the tests comparable.

    Matt L. on #40852


    I just went ahead and purchased TP. The adjusted numbers are

    Run A
    Time 1:19:36
    Distance: 8.84
    Avg Pace: 8:58 min/mi
    Avg HR: 172
    pa:hr: 2.55
    Temp: Temp 79-88 F


    Run B
    Time 1:07:48
    Distance: 6.97
    Avg Pace: 10:24 min/mi
    Avg HR: 154
    pa:hr: -0.38
    Temp: 69-81 F

    Comparing the two now, it seems like Run A might be more representative of my AeT HR/Pace and Run B representing a Z1 pace and HR. Does that check out with anyone’s experience reading these numbers?

    Edit: Scott, I think I was posting as you were responding.

    One follow-up: Are you suggesting that I run at what ‘feels’ like AeT pace and see how the HR shakes out on TP after the fact, understanding that heat might cause the drift to skew high? And then it’s still a matter of rinse/repeat as much as necessary till I get the numbers more focused, as is described in TftUA.

    I will retest and post an update if I have any other questions about the numbers. I also have not yet attempted an AnT test, so that’s a pretty big piece of the picture that needs to get filled out.

    Thanks to all of you who respond to these posts, this forum is a serious gold mine.

    Anonymous on #40948

    Next, I would do an AnT test as a point of reference.

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