Zone 2

[Erik Johnson]

Hi Jordan and Austin,

I’m doing LISS exercise on a treadmill/spin bike 3 times per week and slowly working up to 45min per session (currently at 35min).

I’ve heard a lot about the benefits of LISS or Zone 2 for respiratory health, mitochondrial growth, immune function, longevity, etc., and am looking forward to these benefits.

There seems to be a lot of confusion about the appropriate intensity of this training with regards to heart rate zones: mostly whether if it’s between 60-70% of max heart heart rate or 70-80%.

I have listened to your 3 podcasts on cardio fitness and based on that information I’ve come up with the following guidelines for my training:

1. My estimated max heart rate is 208 - (0.7 x age) = 170
2. Zone 2 for me is 75-83% max HR = 128 - 141bpm
3. The intensity should feel like “RPE 6-7 or at an exertion level that allows you to speak in short sentences, but not sing.” (From BBM GPP article)

Is this an accurate application of your zone 2 discussion in the podcast? I’m going to be spending a lot of time doing this, and I don’t want to build up a whole lot of excessive fatigue because I’ve exceeded the lactate threshold!

I appreciate any feedback you guys can give

[Jordan Feigenbaum]

Erik,

I would favor more RPE 5-6 or so over 6-7 for this application, though I would rely more heavily on HR read outs personally.

I don't think z2 is better for health than z3-z5 and I would not attribute those benefits you listed solely to z2, nor do I think they occur at a higher magnitude with z2 training compared to other zones. I do think that ~ 80% of someone's conditioning training should likely be in z2 from a performance standpoint.

-Jordan

[Erik Johnson]

Thanks Jordan.

So in terms of “I would rely more heavily on HR read outs personally,” and if my goal is to get my heart rate into z2 during training, do you think using 75-83% of my estimated max heart rate would be a reliable way to ensure I’m training in z2?

[Jordan Feigenbaum]

Yea, I think that would be sufficient.

[Erik Johnson]

Great, many thanks Jordan!

[TomBabington]

Hi Jordan,

With regards to this

"do you think using 75-83% of my estimated max heart rate would be a reliable way to ensure I’m training in z2?"

From my understanding (which is probably wrong), zone 2 (assuming the 5 zone model) is considered as training between 65% and 75% of max heart rate. Am I wrong here?

For me, training at 75-83% of MHR would = 140-154 bpm. That's seems a little high for zone 2.

Thanks!

[Jordan Feigenbaum]

Hey Tom,

Great question. Zone 2 in the 5-zone model has been defined and characterized in many different ways. In the literature, based on Seiler and Tonnesson's 2009 paper is one of the first ones to describe HR zones to the 5-zone model and correlate them to the 3-zone model and actual training outcomes. They list z2 as 75-85% max heart rate based on testing. The Norwegian Olympic Federation and Aasen 2008 both use 66-80% max heart rate as zone 2, and the apple watch uses 60-70% max heart rate.

Recent data comparing the 3- to 5-zone conditioning models further defined z2 in the 5-zone model as having the lower bound be midway between 50% VO2peak and lactate threshold 1, with the upper bound being lactate threshold one. I think for most, this is going to be somewhere in the 70-80% max heart rate range, with error bars on either side.

Testing the functional threshold heart rate (FTHR), a proxy for LT2, using Coggan's field test, then subtracting 5% from it would generate the FTHR and allow one use a more specific heart rate zone of 82 to 89% of FTHR.

I don't think 65-75% is a range I'd agree with for zone 2, but it does have a good amount of overlap, for sure.

-Jordan

[TomBabington]

Hi Jordan,

That's quite reassuring actually. I've only got 60-90 mins per week to dedicate to conditioning work (outside of normal day-to-day physical activity) so I want the most bang for my buck with regards to improving CR fitness. I quite enjoy running but was concerned that even running at a relatively slow pace, despite being at RPE 5 and able to maintain conversation throughout, was pushing my heart rate into the 140-155 BPM range (75%-83%) on average, depending on the terrain. So I subbed out running for stair walking, cycling, and brisk walking on an incline in order to ensure that I do the majority of my work in zone 2. It seems that this may not be necessary after all and that I could just stick with running?


Thanks!

Tom

[Jordan Feigenbaum]

I don't think the mode matters as much as the dose. I would prefer a mix of cycling and running in your case.

[TomBabington]

Thanks, Jordan

I was more concerned that my selected mode of conditioning (running) was not compatible with the "zone" I wished to train in. After considering RPE, the talk test, and heart rate (once you corrected me), I'm probably in the desired zone when running at a slow-to-moderate pace.

Interestingly, since I've cut back on the running a little and replaced it with brisk walking and cycling, I feel more recovered for my lower body resistance training and have hit some small PRs over the last few weeks.

I think the plan for now will be to just do one run per week at RPE 5-6, which will predominantly be in "zone 2" and occasionally dip into other zones, and on another day or two per week do some cycling or incline walking exclusively in "zone2", as it's easier to stay within a certain HR range with those activities.


Tom