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HR zones based on 30min LTHR test?

JretroJretro Posts: 7
So a while ago I did a 30min test and took my average HR for the final 20mins. LTHR = 176bpm. Upon calculating my zones, I noticed a big discrepancy between zones 2-3 based on which calculator/website I choose to use. For example...

Based on the British Cycling calculator - -
zone 2 = 119-146bpm
zone 3 = 146-165bpm

Based on this website - -
zone 2 = 140-157bpm
zone 3 = 158-164bpm

For the past 3 months I've mostly been riding around at ~150bpm (I thought this was within zone 2 at the time), but after seeing the discrepancies in these websites I'm not so sure. There is quite a big difference as seen above, enough to mean fatigue vs not fatigue over time.

For a few weeks now, I've slowed down my general riding to ~135bpm. This feels like an easy all-day pace (easy pedalling) which would leave me fresh (as long as not a stupidly long ride) for zone 4-5 training the next day. Back when I was mostly riding at ~150bpm, it required a bit more focus and force to the pedals, and there would be a build-up of fatigue after 1-2 hrs (some breathing, but not lactic acid burning, just slightly fatigued). In hindsight I remember feeling slightly fatigued after a few days riding at this, so perhaps this was tempo/z3 after all?

Now that I'm starting to focus more on threshold intervals rather than easy-moderate riding, I'm wanting to make sure my easy days of no higher than zone 2. At the same time, I don't want to accidentally (if my new zones are wrong) be riding my zone 2 rides "too easy" as I don't have >10hrs/week to ride.

Thoughts on which zones I should go by? What should zone 2 and zone 3 actually feel like?


  • gaffer_slowgaffer_slow Posts: 417
    edited July 2015
    i use Friel's cycling zone calculation, which feels right for me in terms of perceived effort and pacing.
    Friel is pretty well established for HR training - his books are pretty good.

    Training Peaks (free) can auto-calculate it (select Friel cycling from the drop down list).

    Training Peaks will also monitor your rides and suggest LT changes.
    (you get a little notification)

    if you dont want to mess with Trainging Peaks, the zones are:

    Bike Zones
    Zone 1 Less than 81% of LTHR
    Zone 2 81% to 89% of LTHR
    Zone 3 90% to 93% of LTHR
    Zone 4 94% to 99% of LTHR
    Zone 5a 100% to 102% of LTHR
    Zone 5b 103% to 106% of LTHR
    Zone 5c More than 106% of LTHR

    for my garmin I obv only have z5, but i know top of 5a is LT + 4/5 beats

    i tend to ride at the top of zones (which is apparently where best physiological changes can occur), so Zone 2 ride i try and ride within a couple of beats of the top of the zone - same with Zone 3 (although Friel's zone 3 is very narrow).

    For a 'threshold' ride/interval i will ride top of zone 4 and in z5a

    threshold 2x20 (5 minute rest)
    zone 3 2x30 (10 minute rest)

    are the main workouts i do, other than that it is either a fun ride that will involve some threshold climbs, fast descents, a fair bit of tempo (z3) and the odd punchy sprint. Then there is the 3-4 hour top of zone 2 rides.

    The advantage of using Friel's zones is that it matches to his "Total Heart Rate Training" & "Training Bible" books. I am of the thinking of "choose a School of Thought / Theory".
  • JretroJretro Posts: 7
    Interesting. Slightly different again. With this one:
    zone 2 = 142-157bpm
    zone 3 = 158-164bpm

    So do you think for the last few weeks riding zone 2 @ ~135-140bpm (British Cycling Zone 2 = 119-146bpm) I might have been "wasting" my time? (I've found myself questioning how low it's felt at times.)

    I will have to try ~155bpm next time (top of zone 2 for Training Peaks?) and see how it feels. How is it meant to feel?
  • gaffer_slowgaffer_slow Posts: 417
    top of zone 2 will feel brisk but comfortable for 90 mins to 2 hours, as you approach 3 you will be feeling a bit drained. A four hour top of z2 workout will be hard. (all this is dependant on fitness/nutrition so you might start to feel it draining resources earlier)

    Friel's "Total Heart Rate Training" is a great easy to understand introduction.
  • gaffer_slowgaffer_slow Posts: 417
    i find keeping pace at top of z2 is significantly harder than the lower/middle of it.
  • JretroJretro Posts: 7
    Thanks, I'll check out some of those books/sources! Based on what you said about Friel being well established for HR training, I'll probably use these zones instead. Back in March I did a 2-3hr ride at 155bpm and remember it feeling draining toward the end.

    Question: How is z3/tempo (mid,top) meant to feel compared to z2/z4? And how it feel after extended periods?
  • gaffer_slowgaffer_slow Posts: 417
    mid/top z3 will feel a little harder than high2. 2x30 with a 10 minute recovery in between will be pretty draining 8/10 say. 2x20 @ LT 4/5a with 5 minutes in between will be difficult especially the last 5 minutes of the intervals - 9/10 and you will be sore in the evening.

    once you have been doing it a while you get use to gauging the effort you need to put out.
    at first it can be annoying as your heart rate will lag fairly significantly behind the increase in power (HR is a measurement of the body's response to effort - rather than a measurement of effort) so dont be surprised if you overshoot/push to hard (and need to ease off) for quite a while.
  • JretroJretro Posts: 7
    Thanks for the perspective on each zone- very useful. I'll need to check how I feel during 130-155bpm again. After going down from 150 to 135 and thinking my zones were wrong, my perception of each BPM changed as well

    Yes, I noticed that during the 30min test. It took 10mins for my HR to reach 170-175'ish even though I was holding the same speed/effort from the start (no power meter, but it was a flat/consistent road). At first I thought I'd started too slow, but then I remembered from previous workouts (where I'd blown up early) to be sensible.
  • JretroJretro Posts: 7
    @gaffer_slow If I put these new zones on Strava (5 zones only), should the 4th Strava zone consist of z4 AND z5a, or just z4?
    For example: z4 = 165-179 [94-102% LTHR] OR z4 = 165-175 [94-99% LTHR]?

    If the former, then it would make more sense. If the latter, then wouldn't that show a lot of "anaerobic" spent time during a threshold interval workout? Or is that how it's supposed to be. (During my 30min test I was above 175bpm for 15mins+.)

    I read a few pages of Total Heart Rate Training on Amazon. Seems very informative. Will read more tomorrow.
  • gaffer_slowgaffer_slow Posts: 417
    i just set the Strava zones for 5 = 5a+5b+5c. If i havn't deliberately gone anaerobic i know how to interpret it.

    i can see your logic though, and it makes sense. whatever works for you.

    I recently started using the chrome starve addon StravistiX for Strava which allows a custom number of zones so i have 5a b and c. It is a pretty useful "Premium" replacement add on (and free).

    I don't train to power, but i think training to high efforts for shorter intervals, especially training for anaerobic HR is a pretty blunt tool. But needs must until prices drop.
  • JretroJretro Posts: 7
    Your Zone 5 as 5a+5b+5c makes sense actually. If you go slightly above 100% LT then it becomes a lot less sustainable, so I guess you are starting to go "anaerobic".

    Whenever I do a max effort 30s-1min sprint up my village hill, my HR tends to shoot up to 180-183. However with my old zones, I used to have z5/anaerobic set as something higher than this, so I never actually saw it on the data after. At least with the newer zones the graphs will look more accurate/truthful.

    To be fair I won't be using these zones for sprints etc. anyway, but just wanted everything tidy. :D
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