The Karvonen formula is the most common means to calculate your exercise intensity. It’s an equation that blends your maximum heart rate, resting heart rate, and target percentage into one easy-to-use calculation, ideal for endurance athletes.
And while it can over or underestimate the exercise intensity in some individuals. The output typically provides a good baseline starting point.
For example, at moderate-intensity training, an individual may use 59% of his or her HRR, and for vigorous-intensity training, this may be 69%, depending on an individual’s fitness level.
What is the over-under?
Developed by Martti Karvonen, the formula helped apply research to health and athleticism by establishing the role of exercise intensity in improving overall fitness.
At its core, it’s simply your heart rate reserve (HRR) multiplied by the workload intensity and added to your resting heart rate (RHR).
As an example:
A 30-year-old male with a resting heart rate of 65 bpm trains at 80%.
220 – 30 = 190bpm
190 – 65 = 125bpm
(125 x 0.8) + 65 = 165 bpm
As such, this athlete’s target exercise intensity works out to 165 bpm.
In this scenario, your training zones are a function of the difference between your maximum heart rate and your resting heart rate, with age and gender as the largest influencers.
Maximum Heart Rate by Age
HRmax is the traditional method of estimating maximal heart rate. And it’s a relatively simple equation.
Maximum Heart Rate (MHR) = 220 – Age
In 2010, and independently validated in 2014, Martha Gulati et al. further expanded on the traditional method with a new formula for women.
MHR (female) = 206 – (.88*age)
The Karvonen method informally referred to as the heart rate reserve (HRR) formula, considers your resting heart rate by introducing the difference between your maximum heart rate and your resting heart rate.
Heart Rate Reserve
Your RHR is most easily found when you wake up in the morning. Simply measure the beats per minute with technology or take your pulse for an entire minute or over a smaller range extrapolated out.
In exercise physiology and sports science, HRR is the difference between MHR and RHR. HRR is considered to be a good indicator of a person’s physical fitness level.
MHR – RHR = HRR
Increasing Your Heart Rate Reserve Maximum heart rate is mostly age-based and challenging to change with exercise, with modest effects observed from lowering resting heart rate.
But, the heart rate reserve has been found to compare well with the oxygen consumption reserve (VO2R) for estimating exercise energy expended at different exertion levels. So this metric is used to calculate exercise zones for training purposes.
Target Heart Rate
To achieve good early results from training, you should exercise below your MHR to find an excellent aerobic base while allowing your body to recover. This initial preparation provides an opportunity to achieve the ideal intensity level for your short and long term goals.
The Karvonen Formula uses the heart rate reserve number before calculating the heart rate percentage of maximum numbers for target heart rates.
HRR x %Intensity = Target Heart Rate Zone
Long continuous training at sub lactate threshold intensities (target zones) can help lose weight, improve cardiovascular fitness, and general aerobic athleticism for future more ‘intense’ training.
Subsequent, aerobic interval training can result in a more considerable increase in peak oxygen consumption than continuous training and maybe most useful for those at the extremes of exercise capacity.
At which point, you can supplement with anaerobic interval training as the primary modality. While it should be noted that this is not the same as high-intensity interval training (HIIT) and may not elicit the super-fast results people assume.
Karvonen Formula Calculator
Athletes at all levels can benefit from this heart rate data, but it’s particularly beneficial for beginners and casual exercisers. The Karvonen Formula is most commonly used to help keep people from doing too much too soon when starting to exercise or from doing too little, which could end up being detrimental.