How Do I Calculate My Target Heart Rate Zone?

Many Heart Rate Zone Formulas and Theories

Estimating your heart rate zone can be confusing for people when starting a new exercise program. There are so many heart rate zone formulas and theories about projected heart rate; that it can make your head spin just trying to figure out which one to use.

Are the target heart rate calculations accurate? The short answer for a long question is not entirely for the most part. Then the question comes – So why use them at all? The answer is they are a good place to start.

Anyone who has been around the fitness industry or is an avid fitness enthusiast knows if you use a heart rate zone calculator you will barely break a sweat during your workout and never get to your target RPE (rating of perceived exertion). Some calculations do produce more accurate results especially when used in conjunction with other methods.

Most heart rate zone calculators and machines (I am sure you have all seen these HR charts on cardio equipment) use the least accurate theoretical calculation which would be Max Heart Rate. The Max Heart Rate calculation (MHR) requires you to minus your age  from 220. Therefore a 45-year-old person would be 220 – 45 = 175. Once that is established to figure out what your training zone would be, you would times that number by the intensity in which you need to train. Someone new to exercise without health conditions trains around 50 -60 % to start. That means a person who is 45 years old as above, would train at a heart rate of 88 – 105 bpm. Most people would have a heart rate higher than that when they are performing daily activities never mind when supposed to be “working out”.

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Scientists are now saying that the validity of the equation was never established and it will usually always underestimate the intensity of your training zones.

New research by Hirofumi Tanaka, PhD (2), has however produced a slightly more accurate version of this method. The new heart rate calculation is 208 – 0.7 x age. What would that be now for the 45-year-old? 208 – (0.7*45) = 177. Which would be a 2 beat difference and that can be significant when you are in the 80 – 90 % training zones.

It also makes a significant difference when you are getting into the senior population. Looking at the old HR Max calculation a person at 70 years old would be a 9 beat difference! The old method would calculate out to 150 bpm whereas the new heart rate calculation would be 159.

What Calculations Should You Use?

There are a large number of heart rate zone calculations available to use now through different research studies. However, the most common ones used are still the HR Max and Karvonen (heart rate reserve) theoretical heart rate calculations.

The Karvonen formula (HRR) also uses the resting heart rate (RHR) to increase the accuracy when creating a program. The original for the Karvonen heart rate calculation has always been (%) x ((220-age) -RHR) + RHR.

An example of how that works would be if a person were 45 years old to calculate their HRR it starts with 220-45= 175 then you would minus their resting heart rate. An average resting heart rate is 70 so we will use that for this example.

The next step in the formula would be to minus the resting heart rate 175- 70= 105. Then times it by the training percentage 105 x 50% = 52.5 followed by adding the resting heart rate back in 52.5 + 70 = 122.5 bpm.  When looking at the first calculation using the HR Max method the estimated heart rate for working out at 50% would be 88 bpm. The second calculation using the Karvonen would be 122 bpm which makes a 34 beat difference.

How to Get the Most Accurate Heart Rate Training Zone

The most accurate measure of heart rate zones is by doing a graded exercise test (SubMax VO2). The Sub Max V02 test measures the rate of oxygen during incremental exercise. Your max oxygen consumption reflects your aerobic physical fitness and is an important determinant of your endurance capacity during prolonged, sub-maximal exercise.

The cardio analysis machine will compile data, analyze the results and prints your test results with your exercise zones. The zones identified are your warm-up, fat burning, moderate interval levels and high intensity interval levels. VO2 Max is the Gold Standard method to measure fitness. The bottom line: a higher max heart rate = a better ability to intensely exercise. The Sub Max VO2 test results give your peak or the maximum amount of oxygen your body can consume per minute. The VO2 Max has been thoroughly researched and therefore your results can be compared to published values. The test finds your physiological zones and uses your heart rate as a landmark as to where these critical metabolic changes occur.

Hire a Personal Trainer to Make a Program

Working with a certified personal trainer will help you achieve your personal fitness goals in a responsible, safe and effective manner. If you are serious about a future, fuelled by healthy eating, increased activity and infinite possibilities then start with your very own life coach and personal trainer.

Cathie Glennon – BCRPA/SFL