Racing With a Heart-Rate Monitor

I recently had a great experience incorporating my Heart-Rate Monitor into my Marathon racing strategy. If I had gone by pace, I would have taken my recent 10K race result (of 43:58) and plugged that into a Race Predictor, which would have told me to target a 7:43 pace for a 3:22:31 marathon. Instead, I set up heart-rate zones, which ended up pushing me faster earlier in the race and delivered a new PR at 3:18:42, several minutes earlier than I ever imagined possible. The reason it was so successful was that it allowed me to run by feel objectively.

Heart-Rates Bent Out of Shape (Upside-Down “U”)

In the past, pacing bands have turned out to be a painful strategy for me, and many times they have left me feeling burned out by the end of the race, only resulting in an inevitable crash. And it hasn’t seemed to help to just run the first couple of miles 10-20 seconds slower than goal pace. Below is an example from the Stockholm Marathon where I was going for a 3:25, but I wasn’t able to keep up with my negative-split plan. The chart shows heart-rates shooting up and staying consistently over 170 beats per minute before crashing at the 22 mile mark and I wasn’t able to maintain optimal output effort in the last part of the race and I finished with a 3:38. I find that this parabolic Heart-Rate shape is fairly typical of my bad races, where I have been especially optimistic in the morning on race-day.

Unable to Maintain a Hard Effort in the Final 4 Miles

Unable to Maintain a Hard Effort in the Final 4 Miles

The Ideal Heart-Rate Trend

This time round, I accomplished a nice linear upward trend. What was different was that I decided to just run the best possible effort on this given day, regardless of whether that resulted in a PR or not.

Heart-Rate Steadily Drifts Upwards

Heart-Rate Steadily Drifts Upwards from 160 at Mile 4 to 168 at Mile 22.

Benefits of Racing With A Monitor

There are so many variables that affect performance on race day: temperature, rain, snow, hills, sleep, or over-training. While it is difficult to control all these factors, one’s goal on race day should be to produce the maximum output possible. How do you adjust your goal given a hilly terrain? How much should you slow down if it is hot? It is difficult to know and arbitrary to adjust your goal pace for one of these factors, let alone several. Your heart-rate, however, will be lower for a given pace if the temperature is cool and vice-versa. Your heart-rate gives an instant reading into the combined impulse-response to the most complex scenario, for example, a hilly race on a cool day (two conflicting factors) and you won’t have to rely on mile-splits which are averages that might not be as appropriate in the first half of the mile-split as in the second half. When you’re going up a hill the monitor will tell you to slow down, when you are returning back down it will tell you to speed up and that is a feature you wouldn’t easily get with a pace-based approach. A monitor simplifies the racing strategy, pushes you harder if you are feeling good, and responds in real-time to varying conditions.

Heart-Rate Phases

I couldn’t find any good information about how to race with a heart-rate monitor. Even Phil Maffetone, who recommends training with a heart-rate monitor doesn’t go into any details about racing strategies using this approach. So I designed my own strategy using information from recent races along with Eric Orton’s book, The Cool Impossible, which has some useful heart-rate zones:

  1. HR1 is for recover.
  2. HR2 is for fat burning
  3. HR3 is aerobic with some strength
  4. HR4 is for strength endurance.
  5. HR5 is just under your lactate threshold.
  6. HR6 builds muscle and speed endurance helping to develop faster steadier efforts while remaining aerobic.
  7. HR7 is the VO2max level.

For me, the secret to a great race was to start out in the top half of his HR2 (151-156) for the first 3 Miles. And I was really surprised to see myself running faster than what would otherwise have been my ‘goal pace’ already in my warm-up miles. The next 10 miles were in HR3, followed by two 5-mile step-wise increases in the second half.

How to Customize Your Heart-Rate Zones

The way I calculated my particular Heart-rate zones was to use my heart-rates from a recent 10K race. I ignored the first ‘warm-up’ mile and then took the average heart-rate over the next 3 miles (which was 180), and then I cross-referenced that number in Eric Orton’s book. My resting heart-rate is 44 and my max heart-rate is 187, so you could use my working heart-rate percentages below to customize these zones for yourself, without using his table. Your “Working Heart-Rate” is your max heart rate minus your resting heart rate and you multiply that number by the percentage and then add back your resting rate.


Working Heart Rate = Max Heart Rate – Resting Heart Rate

  • 3 Warm Up Miles: 75 to 78% of Working Heart-Rate
    (i.e. Resting HR + (Max HR – Resting) * Percentage = 44 + (187 – 44)*0.75 = 151)
  • Phase 1 10 Miles: 80 to 82%
  • Phase 2 5 Miles: 83 to 85%
  • Phase 3 5 Miles: 86 to 89% (Lactate Threshold)
  • Phase 4 3 Miles: Maintain average Goal Pace to 20 seconds faster
  • Last 0.2: Sprint to Finish

Phase 1 through Phase 3 are all aerobic zones, meaning that you are still predominantly burning fat. Once you reach your lactate threshold you start to burn a lot of glucose and at this point you can stop worrying so much about whether you are spiking any insulin levels because you will be burning less fat anyway.

Putting It Into Practice

The first mile can be difficult with an HR monitor because it relies on some sweat and moisture for accuracy. I often find that my HR monitor can be highly inaccurate towards the beginning of a run, often showing a heart-rate of 170 bpm even though I know it is hardly over 120. Moreover, the excitement over crossing the starting-line will elevate your thumper by several beats. So the first mile or two can be a good time to go by a pace that is about 20-30 seconds slower than your goal pace.

Once you are warmed up, and have reached your target pace, pay attention to your breathing and how it feels to run in that zone. By trying to maintain that feeling, rather than looking at your watch all the time, you’ll have an easier time actually staying within range.

At the Stockholm Marathon earlier this year I maintained my lactate threshold (167-171 bpm) for 16 miles before crashing and when I last PR’d at the Philly Marathon in 2009 I ran the last 13 miles in the 167+ HR zone. This is the info that told me that I could probably do the last 8 miles beyond phase 2 at a Lactate Threshold intensity. By being conservative, it ensured that I had a great time while running and it left me smiling to the finish. If you know you can handle it, you might want to extend Phase 2 with Phase 3. Personally, I found it difficult to maintain Phase 2 in practice and I might consider finding a way to push a bit harder in the second half or extending Phase 1 (80 to 82% range) even further.

The last phase exists in order to push yourself to exhaustion giving you the leeway to really pick it up in the last leg of the race. This is a good time to throw heart-rates out the window and just run for your life. You can make this a bigger portion of your racing strategy if you do more interval/tempo training than I do and are able to sustain high heart-rates for long periods of time.

To really put it into practice, I recommend creating a Garmin Workout to keep the plan on cue:


My watch vibrates and sounds an alert if I drop above or below any of these targets. By using repeated 1-mile splits rather than segments that last 5 miles or more you ensure that the watch creates 1-mile splits the whole way for post-race analysis.

Consistent Mile Splits

Interestingly, my mile splits were actually pretty consistent following this strategy, and the variation more naturally reflected the difficulty of the terrain and allowed me to conserve energy through the hilly first half. Philly is a fairly flat course, so perhaps this shouldn’t be a big surprise, but following a strategy based on Heart-Rates doesn’t necessarily mean that you won’t end up with fairly consistent splits.

Seeing a 7:26 mile split so early in the race would have been alarming to me had I followed a strategy based on pace

Seeing a 7:26 mile split so early in the race would have been alarming to me had I followed a strategy based on pace

Summing It Up

My best races all seem to have in common a linearly upward trending heart-rate. Many times I’ve tried to re-create that experience indirectly by progressively increasing mile-splits, but I can think of several races where that strategy has left me feeling very disappointed. One of the reasons I’ve tended to rely on paces is that there doesn’t seem to be a lot of good information on how to translate your training in heart-rate zones to actually racing in heart-rate zones. Some articles just say to target 70-80% of VO2 max, but what is my VO2 max? Should I use 70% or 80%? How do I use Heart-Rates directly? What if I want to target negative splits? And should I target the same effort the whole way or progressively increase the load? With so many questions, it seemed a lot easier to just pick a goal pace and to work around that.

However, I managed to use the information out there together with information from past races, and I translated things into Heart-Rate zones to come up with a Marathon-specific strategy that worked really well for me and I would recommend giving it a go because on days that you are feeling good, it will push you harder than you realized was possible and deliver a PR beyond your wildest dreams. On the other hand, you might not get a new PR every time, but by avoiding obsession about pace, you’ll end up feeling great throughout the race and it will put you in the mood for the most important thing: to enjoy the race!


About Esotariq

Quantitative Finance Professional with a passion for happy living, self-improvement, nutrition, and minimalist running over maximalist distances.