The Three Challenges of Zone 2 Training

I recently started reading 80/20 Running by Matt Fitzgerald. The general gist of the book (so far) is that most people too fast in their training runs, and should slow down: 80% of training runs should be done at a low intensity level. At the same time, I’ve been reading more and more about zone 2 training — that is, training that stays within a a certain heart rate zone — which is more or less based upon the same principles.

There’s a lot of science and research behind zone 2 training which I won’t even attempt to regurgitate here at the risk of misinterpreting evidence, but it’s convincing enough that I thought I’d give it a go while I train for my next marathon (… err, should probably have blogged sooner, but I’ve entered Edinburgh Marathon 2022). Anyway, I ran my first “zone 2” run on Sunday, and here are the three main challenges I came across:

3. Gradients

It doesn’t take a genius with a biology degree to realise that running up a hill is harder and running down a hill is easier, but I was surprised by how little upward gradient was required to increase my heart rate. I do a lot of hill training by virtue of living at the top of a valley, but found that just a small …well, bump… was enough to easily increase my heart rate into the next zone.

2. Boredom

The next biggest challenge of staying in zone 2 was the sheer unending boredom of going at a pace completely at odds with my usual pace. I felt like I might as well have been walking backwards and I’d have covered the same mileage quicker. It was SO SLOW. That said, despite the boredom, I was so wrapped up in watching my heart rate (because my watch isn’t fancy enough to tell me when it changes zone) that I “ran” for nearly 2hrs without realising. I guess every cloud has a silver lining.

1. My ego

Lastly, but definitely the biggest challenge, was facing off my ego. As well as the general feelings of “I should be going faster than this” and “how’s this going to look on strava at the end”, on the return leg of my ‘out and back’ run I was obviously going in the opposite direction of an arranged event as I saw a lot of joggers with numbers on. Trying to resist the urge to pelt it past them — look ma, I’m a real runner too — was bizarrely hard. I don’t normally suffer with my ego on group runs unless actively challenged; I’m happy to run at anyone’s pace and loop back (no man left behind etc) so this was a bit of a surprise.

All that said, the very obvious benefit of staying in a low heart rate zone was that I was able to just keep going. Although my hips struggled a little with the pace after 9-10km, generally speaking I felt like I could have gone on all day.

After I completed my first zone 2 run and halfway through writing this post, I realised that my Garmin watch had my max heart rate misset, which meant it was calculating my heart rate zones incorrectly. Have corrected my max HR based on a more recent strenuous run my zones have changed and zone 2 is now slightly less tedious to get / stay in – in fact, it’s not far removed my usual easy pace. I did a second zone 2 run in the new zones and the pace felt better, although I struggled for other reasons (fatigue, the fact that it was 6am etc).

I’m definitely interested to continue the experiment with zone 2 training and see how it feels in a few months time… if I can cope with the boredom.

Lead photo by Arek Adeoye


  1. Hi Jem! I’ve been hearing about Z2 training too, so I found this really interesting! Do you know if there’s a minimum amount of time that you need to be running for to get the benefits of being in Z2? I usually run for 40-60 mins and feel like Z2 might just be way too slow.

    • StrongMum

      13 Sep at 9:06 am

      No idea how I’ve only just seen this comment. The folk that know more than me suggest that 70-80% of your training should be at easy or zone two pace.

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