Heart Rate Zones

A critical piece to improving running tolerance and optimizing performance is having an understanding of the heart rate (HR) zone you are training in. There are multiple formulas to calculate aerobic HR. All of them can be used to keep effort at a level consistent with improving cardiovascular fitness and allowing you to continue for more time. Referred to as “Zone 2 cardio”, aerobic exercise involves exercise at 70-80% of maximum HR.

The Fox-Haskell method uses theoretical max HR to calculate the aerobic zone. Max HR is found by taking 220 minus age. For example, a 35 year old would have a max HR of 185 beats per minute (bpm). This is multiplied by the percentage of effort desired. For an aerobic workout this would be x0.7-0.8. Using 185 as max HR, a 35 yo will have an aerobic heart rate zone between 130-148 bpm.

The Karvonen method factors in resting HR as well, which is often recorded by smartwatches. Resting HR is subtracted from the maxHR, this number is then multiplied by desired effort, followed by adding the resting heart rate. For a 35 yo with a resting HR of 55 bpm the formula would be: (185-60) x % effort + 55=target HR. Using 70%-80% to find the zone, the range is 146-159 bpm. One advantage to this formula is that the range will change as resting HR improves with consistent training.

An easier calculation is the Maffetone method. This takes 180 minus age for the top of the aerobic zone. Therefore you would want to maintain a heart rate at or below this value during the run. With the same example, a 35 yo would use 145 as the top of their aerobic zone (180-35=145 bpm).

Even simpler is the “Talk Test”. This means that if you can complete sentences as if in conversation while running, you are likely within the aerobic HR zone. This is certainly a great option if you have no method of monitoring HR during your workouts.

Each method has advantages and disadvantages in terms of convenience and adaptability. Advancements in wearable technology have made it easier than ever to monitor your heart rate. We hope you can use these formulas to take your training to the next level!