Help me find Zone 2

I’ve been hearing a lot about the advantages of Z2 training in the last few years. Occasionally I will go out with the intention of riding in Z2, but it is very difficult on the road and the Sufferlandrian in me soon finds myself going harder. However, I have hit a bit of a barrier in my training and it’s definitely time to try something different or I will keep getting the same result.
I did a 12 week 3:1 Moderate Volume All Purpose plan earlier this year and successfully completed almost every ride, yoga session and strength training. This culminated in my best ever results in the Half Monty and best ever assessed FTP and MAP.
I tried a repeat of the same Plan but failed to find the motivation and struggled to complete sessions. I paused for a few weeks and restarted but failed again. Time to try something else!
So I have started a Base 4-week plan, 3:1 high volume with yoga.

The first question is what heart rate my Z2 should be. I think I am quite atypical. I’m 53 but have a high max heart rate, but also fairly low resting rate. My rest heart is low 50s. My max is definitely over 200bpm. Even at the weekend I had 198-199 on two separate climbs and I wasn’t going especially hard. In my most recent Half Monty I reached 200bpm. Last year I saw 208bpm on a climb when going hard.
Possible reasons for my high max heart rate are that I am permanently slightly anaemic and I had some treatment with doxorubicin in 2012 and 2018 that caused damage to my heart and reduced ejection rate. I think my heart has to work harder since then to compensate.

According to the Half Monty test my cTHR is 178bpm, but I find I feel that from around 170bpm I am putting in an effort that would be hard to sustain. (I don’t know if this is how threshold should feel.)

So the questions:

  1. According to a Systm my Z2 should be 123-151. Does this seem about right?
  2. If I am going to train in Z2 is training at the top end of Z2 more beneficial than lower in Z2?
  3. I’m sure, all those years ago, when I started using The Sufferfest, I put in my max heart rate. This will inevitably reduce over time - only a few years ago I saw 214bpm. Is there a way to edit the Max Heart Rate is SYSTM?

SYSTM Z2 and Training Advice for Your Situation

Here’s a breakdown of your questions and some advice:

1. SYSTM Z2 Range (123-151bpm):

  • It seems like a reasonable starting point for your Z2 based on SYSTM’s formula. However, with your unique physiology, it might be a bit high.

2. Training at the Top vs. Lower End of Z2:

  • There isn’t a significant difference between the top and lower end of Z2 for pure fat burning. Both promote recovery and aerobic base building.
  • You might find the lower end (around 123bpm) more sustainable for longer Z2 rides.

3. Editing Max Heart Rate in SYSTM:

  • Unfortunately, SYSTM doesn’t currently allow direct editing of your max heart rate.

Here’s what you can do:

  • Test your own Z2: Find a flat terrain and do a gradual increase in effort, noting your heart rate at different perceived exertion levels. This can help you establish your comfortable Z2 zone.
  • Use cTHR as a reference: While 178bpm might feel high for sustained efforts, it’s your cTHR based on the Half Monty test. Consider starting slightly below (170-175bpm) and see how it feels.
  • Focus on perceived exertion: Listen to your body. Z2 training should feel conversational, allowing you to hold a conversation without gasping.
  • Update your max heart rate (if needed): If you have recent data showing a lower max heart rate (say, from a lab test), contact Wahoo support to see if they can manually update it in your profile.

No, but you can edit your cTHR and the zones that SYSTM calculates will recalculate based on that edit. SYSTM takes your cTHR and makes it the top end of your Threshold HR then says anything greater than that is your “Max”.

@Fantom, if your HM cTHR was 178 and you feel that around 170 would be hard to sustain, I’d suggest your cTHR is probably fairly accurate. Threshold or near threshold should feel hard to sustain. Think Defender, Long Scream, High Time, HHNF, UCI Road etc.

Edit: I have no advice to add to help you find your Z2. But you can edit your SYSTM cTHR and see how different vids feel as @warner suggests.


According to Inigo San Millan the reason for HR Z2 training is to promote increased mitochondrial function. This will both increase your aerobic engine (FTP), and general health because mitochondria seem to be involved in several major areas of health.

If I recall correctly, he encourages staying in the higher end of Z2.


Thanks all. Sound sensible advice there.

@Heretic That’s what I seemed to remember - best benefits to training come from the upper end of Z2.


Fitness is proportional to total training load which is equal to volume x intensity

How many hours of Z2 are you going to be doing?

Fuelling is a major issue as Z2 intensity increases you burn more fat but also a lot more carbs. For me bottom end of Z2 is 520Kcal/hr top end is 750Kcal/hr, I don’t have any problems doing 6-8hrs at top end of Z2 HR every week, but the 20hrs( if I had the time) at that intensity would break me even if I could eat enough!

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Z2 is hard to keep to outdoors.

The plan has about 6-8 hours per week. That is ambitious for me and so far I have been managing 5-7 hours.