Tracking Heart Rate-Pace Relationships

“...monitoring your heart rate-pace relationships in your run training is a great way to track your progress toward peak fitness and help you make adjustments when necessary" - keep reading Matt Fitzgerald’s article below.

Matt Fitzgerald is a journalist, author, coach and runner specializing in the topics of health, fitness, nutrition, and endurance sports training. (read his blog) Matt uses TrainingPeaks software to provide his pre-built training plans for runners, basing his workouts on the different pace zones that runners training for certain distances should focus on throughout the season.

Article by Matt Fitzgerald

The relationship between your pace and your heart rate changes as you gain (or lose) fitness. Tracking these changes is an excellent way to assess the effectiveness of your training. As you train toward peak race fitness, you should find that your heart rate decreases at any given pace and that, at any given heart rate, your running pace increases. You should also find that you can sustain any given heart rate for a longer period of time before fatiguing. Finally, you should find that your threshold heart rate—the heart rate associated with your threshold pace—increases as your threshold pace itself increases (but not to the same degree). This simply means that you are able to sustain a higher work rate over a given period of time. Note that all of these changes are relatively small and gradual, so don’t look for improvement between Tuesday and Wednesday.

You can formalize the process of tracking changes in your heart-rate pace relationships by performing periodic specific endurance tests. A specific endurance test is a workout that tests the effects of your recent training on your efficiency at your race pace for an upcoming event.

Let’s suppose you’re currently training for a half-marathon. Step one is to come up with a ballpark estimate of your current half-marathon race pace in the context of doing your normal workouts involving efforts at this pace. Wear a heart rate monitor during these workouts and note the heart rate that is associated with your current half-marathon race pace. This is your half-marathon heart rate, which will not change much between now and your goal race. What will change is the pace you can sustain at this heart rate. You’ll have achieved peak race fitness if and when your half-marathon heart rate and your goal half-marathon pace match up.

Now you’re ready for your specific endurance test. Go to the local track and, after a thorough warm-up, run for 20 to 30 minutes at your half-marathon heart rate. Stop after the designated test duration has elapsed and note how far you’ve run. Use the time and distance data to calculate your pace. Repeat this test once every five or six weeks. You should move closer to your goal half-marathon pace each time.

If you train with a speed and distance device that has heart rate monitoring capability, every stride of every run you do can be used to measure changes in performance through analysis of heart rate-pace relationships. When analyzing the workout data you’ve downloaded into your training software, simply choose a segment of a very recent run in which you maintained a fairly steady pace and note the corresponding average heart rate. Now go back a few weeks and find a segment of a run in which you averaged the same pace over the same distance. If the corresponding average heart rate is higher in this earlier workout, you have pretty good evidence that you’ve gained efficiency at that particular pace. You can make this type of comparison for any pace: a very fast pace run in short intervals, your goal pace for an upcoming marathon, your standard aerobic pace, or any other pace you run with regularity. Failure to gain efficiency at a particular intensity level over time indicates that you need to increase your focus on training at that intensity level.

You may also use heart rate/pace relationships to track changes in your endurance. During prolonged running at any steady pace, your heart rate will hold steady for a while and then begin to slowly increase due to decreasing mechanical efficiency. This phenomenon is known as decoupling. As your endurance increases, you will be able to go longer at a given pace before your heart rate and pace become decoupled, and the degree of decoupling will decrease.

Make a habit of measuring your decoupling in each of your long runs exceeding one hour in duration. According to coach Joe Friel, well-trained endurance athletes are typically able to keep their decoupling ratio below 5 percent. If yours is above 5 percent you will need to put greater emphasis on endurance training until it falls below the 5 percent threshold.

Users of TrainingPeaks WKO+ can easily view and track their daily decoupling ratio within files that include heart rate and pace data. The below screen shot shows a run file and where to find the Pace:Heart Rate decoupling value.

There’s no value whatsoever in monitoring your heart rate in isolation. Event directors do not award prizes to the athletes who achieve the highest or lowest heart rates in races. However, monitoring your heart rate-pace relationships in your run training is a great way to track your progress toward peak fitness and help you make adjustments when necessary.