A Guide to the Rhythms of Running
How can heart rate inform your training?
There are many ways to estimate your effort level when training. In previous posts, we have discussed how rate of perceived exertion, lactate testing, and pace calculators can be implemented to estimate your running workload at various intensities. Another commonly used metric to inform training is heart rate. Heart rate is easy to monitor, and when contextualized, it can provide valuable insight into endurance training. Let’s explore how you can use heart rate monitoring to enhance your running performance.
Unlike lactate testing, monitoring your heart rate can be done with minimal equipment. At the most basic level all it requires is a clock and taking your own pulse. Additionally, many of us have a basic heart rate monitor built into our wristwatch. For more frequent and accurate readings, you can go one step further and use an inexpensive heart rate monitor connected to a chest strap that provides real time readings on your GPS watch.
As you are likely aware, modern technology spits out a lot of personal data at us everytime we upload a run or open your training app of choice. However, if you're like me, you may find yourself questioning at times whether or not these charts and graphs have value. Most fitness apps will break down your training into “zones”. The accuracy of these zones depends on how closely these percentages line up to YOUR Heart Rate Max, and the accuracy of your heart rate monitor.
Let’s walk through the basics of Heart Rate Max.
Heart Rate Max is the highest number of beats per minute your heart can reach during the most strenuous exercise. Unless you have done specific exercise testing, this is usually an estimation. There is significant variability in the equations used to estimate an individual’s HRmax, so keep this in mind that the charts your fitness app is spitting out is based on an age graded estimate. There is going to be considerable variability amongst individuals.
There are multiple formulas out there, but here is a common equation to predict HR max:
HR Max = 208 - 0.7 x your age
This equation is widely implemented. It is true that max heart rate is most influenced by age. Factors such as physical activity level and gender have minimal impact on HR max. However, this equation has its limitations. Most research on HR max has been performed on healthy college-aged subjects, and this equation has been found to underestimate HR max in individuals over the age of 30.
On a personal note, when performing higher effort anaerobic work, and when racing, it is not unusual for my HR to spike around 200 bpm, which is well above what standard equations predict. That is to say, that when using an age-adjusted equation to determine HR max, if you are over the age of 30, recognize that there is a 10-11 bpm variability. Your heart may very well be capable of reaching a higher than predicted cadence.
Oftentimes, training is categorized into various “zones” based on percentage of heart rate max.
Zone 1 - easy - 55 - 65% of max HR (warm up/recovery) - This zone can include light jogging, easy cycling, or walking. The rate of perceived exertion should be low, meaning you could maintain this exercise level for a long period of time. This zone is sometimes referred to as the “fat burning zone”
Zone 2 - aerobic - 65 - 75 % of max HR (easy/aerobic/base) - This is the zone you should be in for your easy, recovery day runs. You should be able to hold a full conversation at this pace. Depending on your fitness level, this zone may include brisk walking.
Zone 3 - tempo - 75 - 85% of max HR (aerobic/tempo/steady state) - this is the zone you should be in for longer efforts, like marathon training runs and long tempo efforts. This zone is described as “comfortably hard”
Zone 4 - lactate - 85-90% of max HR (threshold/lactate threshold) - There is some overlap between zone 3 and 4, but these two zones are where your lactate threshold workouts should fall.
Zone 5- anaerobic 90% of HR max and above (maximum/anaerobic) - This is your all out effort, and is likely where your heart rate will get to in a shorter, fast race or with hard interval training. You can sustain an effort in this zone for the shortest amount of time.
As mentioned in the previous threshold training article, the best way to determine your heart rate ranges in a given training zone is via individualized testing, such as those used for threshold training. Again, because research is conducted on young healthy individuals, it is possible that older individuals’ HR max can be higher than the equation predicts. As a master, don’t sell yourself short when training.
Zone 2 Training
Athletes often refer to “zone 2 training”. What does this mean? Zone 2 roughly correlates to mild to moderate intensity cardio exercise, as discussed previously. Zone 2 exercise is performed at a level in the 60-75% of HR max. Performing your easy runs here can help you avoid the pitfalls of working too much on easy days, and sabotaging your recovery between workouts.
One study assessed the impact of predominantly middle zone (around zone 3 on the above scale) training, to a more conventional training program of mostly zone one, and some zone 4 -5 training on 2k time trial performance, and found similar results between training groups. This seems to indicate that doing more training in the middle zones, not at an all out intensity, saves 17% of time in recreational runners while having a similar training effect. This finding is in line with the research mentioned early regarding the lactate threshold training method.
Now it’s time for you to tune in to what your heart beat is telling you about your training! Heart rate training is one tool of many to guide you in your training efforts. What zones do you spend most of your time training in? Once you have familiarize yourself with the heart rate training basics, in Part 2, we will dive deeper into what your heart rate may be telling you.
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