Follow Your Heart to a Marathon PR

by Kirt West

In my summer footnotes column, I outlined a program for running your first marathon with a heart monitor. This column offers an alternative for those frustrated veteran marathoners whose times do not correlate with their race performance at shorter distances.

How do you know if you are one of those who should try to run their next marathon using heart rates? First, consider this method if your marathon times are significantly slower than your results in shorter races. You should be able to run a marathon at a pace of one minute per mile slower than your 10K race time.
Even if you have a gap of more than a minute and a half between marathon and 10K times, you need to look for defects in your training before considering using heart rates. Did you do long runs up to 22 miles every other week for a 12-week period before the marathon? Did you do any training at Predicted Marathon Pace (PMP)? Did you do any speed work such as anaerobic thresholds at 80-85% of maximum heart rate (MHR) that equate to your 15K or 10-mile race pace? Were your recovery days at 60-70% of MHR? Did you taper down at least 3 weeks before the marathon? Did you go out too fast? Did you get dehydrated during the race?

If you are convinced that neither training nor mistakes in race strategy caused your slow marathon, then the heart rate approach might be for you. You may get so nervous about the marathon that you completely psyche yourself out. Or you may have problems with pacing.

Caveat: Racing a marathon by heart rate might not provide the results you are hoping for. If you embark upon this endeavor, your goal will be to match your goal pace with heart rate. This is not easy, because doing training runs at PMP is not the same as what happens when you pin a number on your chest and enter a race. My information on this subject is anecdotal and results are greatly varied.

To prepare for your heart-rate marathon, incorporate several PMP runs of 5-12 miles into your long runs. Because this kind of training can really beat you up, you should take off the days before and after one of these demanding runs and do no hard training runs 3-4 days before or after the PMP run. As you run, you must get feedback from your heart monitor and observe how much your heart rate increases at PMP. These numbers will be critical in determining what heart rates to use in the marathon.

Your marathon effort should be in three zones. Zone 1: Try to run at a constant heart rate for the first 13 miles. Zone 2: Miles 13-20, strive to increase your heart rate by 3-4 beats. Zone 3: From mile 20 to the end, increase rate another 3-4 beats. Zone 1 will be approximately 80% of MHR (using the Karvonen formula described in my Summer footnotes column). Zone 3 will be 85% of MHR; however, do not arbitrarily set Zone 1 at 80% because your anaerobic threshold can vary depending upon your level of fitness and may be higher than 85%.

Once you have determined these numbers, find a relatively long race, at least 10 miles, preferably a half marathon, to test them. You need to be totally rested. Try to run the entire race in Zone 1 to see if the pace gives you the results you are hoping for. Running a half marathon or 10-miler at this effort level should be somewhat easier than racing it at an all-out rate.

I would appreciate feedback from any readers who have run or plan to run a competitive marathon based on heart rate.
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Coach Kirt West is a private coach for motivated adult runners and a member of the Montgomery County Road Runners Club. Questions for him can be sent to kirtwest@erols.com.