Heart Rate Drift & staying in zone 2

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April 20, 2020 at 10:28 am #40688

jonathanmichaelryan
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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?
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Posted In: General Training Discussion

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Brett on April 20, 2020 at 2:53 pm #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.

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OwenFW on April 20, 2020 at 6:19 pm #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!

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Brett on April 23, 2020 at 7:42 am #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.

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cnikirk on April 23, 2020 at 10:43 pm #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.

Inactive

Anonymous on April 24, 2020 at 9:12 am #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.

Participant

Al B on April 24, 2020 at 1:19 pm #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.

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OwenFW on April 24, 2020 at 1:41 pm #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.

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Matt K on April 25, 2020 at 7:39 am #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.

Participant

Matt K on April 25, 2020 at 7:48 am #40897

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

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Anonymous on April 27, 2020 at 12:46 pm #40949

@fargoan: What’s the short answer? 🙂

Participant

Jan on May 16, 2020 at 12:21 am #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.