Let’s talk about heart rate training

I’ll be honest- when I originally started wanting a Garmin it was just so I could look down at my wrist real quick to see how far I’d gone, how fast I was currently going and what my overall average pace was. I hadn’t really thought much beyond that, I didn’t know a thing about heart rate, zone training, etc. I imagined that the chest strap thing you had to wear would be uncomfortable and that the only new data you’d get was a more accurate count of calories burned. Oh Ashley, you were so naive!

I was so excited to use my new toy but I kept putting off setting up the HRM, it seemed like more work and it was definitely more reading so I set it to the side. K. was not too pleased with this, as he had done the research/bought this for me he said the HRM was a huge reason why so I should start using it. I complied and 2 minutes later (seriously, it was not complicated at all) I was strapped in and ready to go. I set out for what I told myself was an “easy 6” and I was interested in seeing where my heart rate fell. 

Average HR: 173bpm, 85%ish of max HR. AKA, quite high for an “easy” run.

My initial reaction was to get really defensive and swear that the run felt easy and that I definitely could have held a conversation (what I aim for on easy or recovery runs) but the fact of the matter was that this fancy device probably wasn’t lying to me. Time to start doing some research.

I started reading as many articles and blog posts as I could to learn what exactly these “zones” were and how they were going to help me become a better runner. Runner’s World breaks it out nicely here. Basically there are four zones: recovery, aerobic, threshold and VO2 max. The zones are defined by the % of your max HR (which can be calculated many different ways but I went with the super easy 220-age, which might also be quite inaccurate). After I input my resting HR (55) and my quickly determined max (193) I could see what each of these zones would look like for me. 

Here’s a quick glance at what training in the each zone does:

Recovery Zone:  Training in this zone improves the ability of your heart to pump blood and improve the muscles’ ability to utilize oxygen.  The body becomes more efficient at feeding the working muscles, and learns to metabolize fat as a source of fuel.

Aerobic Zone (or Target HR zone): Most effective for overall cardiovascular fitness. Increases your cardio-respiratory capacity: that is, the your ability to transport oxygenated blood to the muscle cells and carbon dioxide away from the cells.  Also effective for increasing overall muscle strength. Most of my training will be done here.

Anaerboic Zone: The point at which the body cannot remove lactic acid as quickly as it is produced is called the lactate threshold or anaerobic threshold. It generally occurs at about 80-88% of the Heart Rate Reserve. Training in this zone helps to increase the lactate threshold, which improves performance. Training in this zone is hard: your muscles are tired, your breathing is heavy. Speed work days, yay!

VO2 Max Zone: You should only train in this zone if you re very fit, and only for very short periods of time. Lactic acid develops quickly as you are operating in oxygen debt to the muscles   The value of training in this zone is you can increase your fast twitch muscle fibers which increase speed.

The training plan I’m using (a mix between Jenny Hadfield’s Intermediate Half and Beginner Full ) conveniently has the desired HR percentages right underneath the daily workout. I set out to do a 50 minute run while keeping my HR in the 65-75% range. How the run felt: SLOW. Turtle slow. I kept looking down at my watch (which I had set so I could only see my HR, not my pace, because I knew that my ego couldn’t handle the blow) and having to slow back down to keep my HR in the right zone. I ended up doing 5 miles in just under 52 minutes, which is only 2 minutes less than it had taken me to run 6 miles a few days earlier. But at the same time, the run felt good. None of my aches and pains were acting up and I felt like I could have ran forever without a problem, which is exactly the point of training in the aerobic zone. 

While I was nursing my still slightly bruised ego I stumbled across this blog entry over at Shut Up and Run that I found to be really helpful. I had always thought that one could only over train by running too often (every day) or too far before they were ready but it’s very likely that I’ve been over training by simply running too hard on every.single.run. I probably haven’t had a proper recovery run in well over a year. It explains my constant injuries, my heavy lead like legs and why I was having so much trouble increasing my distances last training cycle. I kept maxing out at 20-25 mpw when I really wanted to be in the 30s. It’s a pretty big wake up call, actually.

So where am I at now? I kind of feel like I’m starting over with running. I’ve been approaching runs in a very different way. It’s been a bitter pill to swallow, seeing my times drop so drastically, but I’ve been feeling really strong. Recovery after my 8 miler was a breeze and I had no pain the next day. Running slower is going to be hard for awhile, but I’ll have speed work days to look forward to and I know that by being able to log more miles (because they will be less hard on my body) I’ll see an increase in pace over time. 

Whew, that was a lot! And there is so much more to learn still. There are truthfully so many great running resources and blogs out there that you can lose hours looking up something simply. I definitely plan on keeping you updated on my zone training and hope to add in a weekly training round up post. 


  1. You might want to check out the Zen and the Art of Triathlon podcast. He talks a lot about gauging you HR zones by feel instead of by monitor. Yea that's good stuff! Most people (myself included) don't take the easy runs easy enough. I have a friend that doesn't think it's possible for me to run 8 miles easy over lunch because there is no easy way to run 8 miles. crazy talk.

  2. Thanks for the recommendation! I was truly shocked to discover just how slow I have to run to stay in my aerobic zone, I thought I was much more in tune with my body. Always more to learn, apparently.

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