Week 3: Heart rate training diary – HR starts making sense

While one PB got smashed, a poor performance inspired a moment of clarity…
Week 3: Heart rate training diary

New to the diary? Let me bring you up to speed: I'm working on a training plan with Fitbit's ambassador and former Olympian Greg Whyte on how to use heart rate information to become a better runner. My big question is simple: it's all well and good having a heart rate monitor on your arm, but how do you use it to actually get fitter?

Last week you might recall being a bit of a false start with the heatwave that engulfed London – but as the temperatures eased, this week has been much better.

I decided to repeat week two of the training schedule this week, since my original attempt was ruined by the heatwave. This was because week three ramps up significantly, and I want to make sure my legs are prepared. And it was a week full of learnings…

PBs and me

The first run was a 45 min at LT, including 20 mins at AT2 (check that box over to the left for translations), which I have now worked out to be approximately 165bpm and 175bpm respectively.

Learning from the week before, I hit the road at 175bpm early on, and tried to scale back to 165bpm after 20 minutes. At 45 mins I still felt fresh and opted to carry on to 10K to see how my PB stacked up: 52:52 was the final time, a big PB and a win for heart rate training, too.

Looking back at my heart rate data, I found two interesting parts. Firstly, from the end of the run I now believe that my AT2 HR is closer to 180bpm, so I could have gone harder in the first 20 mins. I also found it very difficult to get my heart rate down to sub-170bpm after the initial blast. On the graph below you can see a dip in pace, yet very little change in heart rate. I'll be catching up with Greg about why this was.

Curiously, though pace dipped off after the initial 20 mins heart rate didn't

Going with intervals

Next up was five sets of 2 x 200 sprint intervals. The least said about this the better. I hate sprint intervals with a passion. The first few sets were easy and the two minute rest breaks seemed like an eternity, but four sets in and the rests seemed fleeting.

It was hard going and the run left me stiff in my hamstrings, something that took effect in the last run of the week: a 5K race. This 'race' had to be done in my local park, and was a solo run against the clock. I was sure it would be a PB yet it was over a minute slower than my best. My heart rate also escalated through the run gradually and I had little left at the end. The tiredness of four runs in a week certainly played into the time, and left me wondering how I'd cope next week with much more time on my feet.

Greg Whyte has been building a plan, and guiding me on heart rate

The breakthrough

But it was my second 45 minute run at at LT (165bpm), which was to cause the biggest revelation of the week. This is my base level marathon pace run, and the third of this dairy – it's the run that's going to be the focus of my MISO cycle comparison in week six, and the best indicator of my improving fitness.

But there was an issue: the week before the same run was hillier, yet I was 20 seconds per mile slower this week at the same heart rate. Why? The slower run was in the morning, could that be it? Was it what I ate the night before? Or drank?

And this is where heart rate training comes into its own. I had a revelation.

By training with heart rate, I could find the answers to these questions. Because heart rate is the constant, if I set up a spreadsheet (stay with me here) of my runs, I could try and find a correlation between when I was hot and when I was not. And that's how you really start to use heart rate for your training.

9:40 average pace was a whole 20 seconds slower than last week at LT

So I set one up. It's probably the geekiest thing I've ever done when it comes to fitness, but was it possible to ascertain the foods, times and preparation that correlated with my fastest runs? Well, perhaps by the time my first MISO cycle end in week six, I'll have the answers. I'll share it next week when it has a little more data.

But I'm now closing in on establishing my heart rate zones: 165bpm is LT, 175bpm is AT1 and 180bpm for AT2. My sprint intervals got me up to 190, which is a few beats shy of MHR. Getting a feel for these heart rates has taken a few weeks, but knowing the levels is helping to pace my training, giving me confidence about long runs and making my sessions more efficient. And if this spreadsheet thing works out, I may understand what powers my good runs, too.

So it's all good. But next up I have to tackle week three's gruelling schedule. Check in next time to see how I get on.

Check out our heart rate training series:

Week 1: Getting assessed

Week 2: Feeling the heat


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3 Comments

  • adammiarka says:

    Like reading your progress thru this. I've recently started training for a half marathon, but have decided to use heart rate and time vs distance. I've setup my program via Polar's running plans. Took a little bit to get used to, but my runs feel much better. Once I actually changed my zones from max heart rate based to HRR (heart rate reserve), it feels much more realistic for effort.

    Looking forward to your updates. 

    • j.stables says:

      Would be good to hear about your Polar Flow experience. And also, let us know your LT threshold heart rate (marathon pace), too.

  • Phil says:

    Great article. I'm an on-again, off-again HR training user. Quite honestly I find pace to be easier to use with when trying to hit specific training intensities (such as threshold runs, intervals, and LSDs).For me, HR really shines when trying to maintain a slow recovery pace. Running at recovery 'pace' just seems too slow. Running at a recovery HR is more palatable (even though it's the same slow pace -- go figure.) The other time I used HR to govern my pace was when I was on the bike before the run leg of a triathlon. Again, 85% effort just seemed too easy but having a nice concrete number to shoot for made it acceptable.

    HR reacts a little slower than your actual pace; it takes several moments for your HR to ramp up or down with your actual exertion so I've always had problems using it for short bursts like intervals. I notice that you're using Strava HR graphs. I love Strava but I've always been frustrated by it's inability to zoom in on a specific portion of your run and give you your average HR (or pace) for that exact piece. In your LT run shown above you don't seem to have started with a warm up (or, if you did, you restarted your watch after the warm up). I've got another option for you: download your .gpx or .tcx file from Strava or Garmin onto your computer and then open that file onwww.GraphMyRun.com.Click and select the portion of your run you want to analyze (so, for example, exclude your warm up and cool down) and GraphMyRun will automatically calculate your average HR (and average pace) for just the selection you picked. That's handy if your intervals or your run doesn't start or end exactly on a one mile lap.

    Cheers!

    Phil (author of GraphMyRun)

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