Heart Rate Drift & staying in zone 2

  • Creator
  • #40688

    On my longer runs (over 2:30:00) I find it hard to keep my heart rate in my AeT zone without my pace dropping significantly. It never drifts too high. Normally about 5 beats. When it does drift higher my breathing rate and my perceived effort are low. When I am not watching closely I naturally fall into an easy pace that is higher than my AeT HR (only toward the end of long runs). Should I follow my breath/effort and let my HR drift the addition 5 beats or follow my HR to stay in zone? What is the relationship between cardiac drift and zone training?

  • Participant
    Brett on #40701

    I notice the same exact thing in my long runs right around the 2.5 to 3 hour mark. Still feels super easy, but my HR is 5-10 beats higher than AeT. I’ve noticed that this elevated HR is very close to the AeT value I would need to no longer be aerobically deficient.

    OwenFW on #40711

    I don’t worry about it as long as my breathing is normal for the zone. I just figure it’s been too long since my last full AeT test, and I’m fitter now. Man, I hate those tests. Following to hear what the coaches say!

    Brett on #40815

    Found an interesting article on this: https://runnersconnect.net/coach-corner/why-cardiac-drift-is-important-for-runners-who-train-by-heart-rate/

    Not sure how accurate the statement is, but the author states “the stroke volume of the heart decreases so that cardiac output and oxygen uptake remain the same, keeping your breathing and effort similar while heart rate rises.”

    I’m really torn, as I would LOVE to go by perceived effort on my long runs and not be a slave to the readings on my watch, but if I were to do so I would be spending quite a bit of time above AeT and possibly inhibiting progress. Also, my body doesn’t do well in heat, so I believe my drift may be more severe than most, especially now that the days are getting quite warm here in central TX.

    cnikirk on #40841

    I’m curious about this as well. Same thing for me, especially after about 90 minutes in my HR starts to drift up then at the end of 3 hours, I have to fast walk to stay under AET. Would like to know if staying under AET the entire time is the right thing no matter how much you have to slow down or no? I believe based on what I have learned here, that you should stay under AET the entire time but no entirely sure on these long workouts.

    Anonymous on #40855

    Good question. Heart rate measures stress, so as stress increases, so will heart rate. On a long run, increases in stress can come from heat, fatigue, dehydration, muscle damage, etc.

    For that reason, I lean toward thinking that AeT pace is more important than AeT HR.

    BUT! I also think that going by Rating of Perceived Exertion (RPE) is a joke. And if you combine RPE with the cognitive biases we all struggle with, it’s a recipe to gradually justify going too fast too often.

    So going by heart rate, even if pace declines, is conservative. But conservative is always better than being too optimistic.

    Al B on #40871

    This doesn’t quite answer the OP’s original question but Stephen Selier posted an interesting presentation on some of the same topics here: https://www.youtube.com/watch?v=3GXc474Hu5U

    He’s talking mostly about the relationship between %HRR and %6 min power for cyclists but it seems like the concepts are transferable.

    OwenFW on #40872

    Scott’s answer suggests some remedies: start long runs slower (advice I’ve received previously about race pacing), hydrate better, increase run-walk ratios, get stronger, etc. Working an intentional run-walk ratio into my longest runs as practice for doing it in races of increasing distance has been something that’s been on my radar for a while, but I haven’t been able to get over myself because it feels like cheating.

    Matt K on #40895

    Listening to episode 310 of the Endurance Planet ATC podcast might help answer the OP questions. You can skip to 35:15 for the short answer but listening to the whole episode is beneficial IMO.

    I’ve been listening to Endurance Planet ATC (Ask the Coaches) series of podcasts for several years, about the same amount of time I’ve been following TFTNA. I find a lot of similar philosophies in the two.

    Matt K on #40897

    Meant to say skip to 36:15 for the short answer

    Anonymous on #40949

    @fargoan: What’s the short answer? 🙂

    Jan on #41768

    In this video, starting around min 5:30, Steve House kind of says that you shouln’t go over AeT in your long runs.

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