Your heart is the engine of your body; how fast it pumps can provide you with vital information on how well your body is doing while exercising.
It’s critical that you learn how to calculate your optimal heart rate zones, comprehend the meaning of these zones, and how to use that information to meet the specific fitness goals you’re aiming for.
What is Your Reserve Heart Rate?
Your heart rate (measured as beats per minute) ranges from its lowest – your resting heart rate to a maximum (past which it will not go) that you can only achieve when under the most intense exertion. Within this broad range, your heart rate can be further divided into four particular zones:
- The fat-burning zone
- Your aerobic fitness zone
- A transitional zone called the aerobic/anaerobic zone
- A purely anaerobic zone
To discover what the heart-rate that brings you in particular into a specific zone; you’ll need to calculate your reserve heart rate.
We can do this by first calculating our maximum heart rate. Just subtract your age from 220 to discover your age-predicted maximum heartbeats per minute.
It’s easy: Let’s say your age is 45, you need to subtract 45 from 220 and 175 beats per minute (bpm) would be your maximum heart-rate.
Next, find your resting heart rate by taking your pulse for one minute when you’re at rest. The recommended time to do this is when lying in bed before getting up in the morning, and the best spot to use is your throat (the carotid pulse).
Finally, your heart rate reserve is the number you get after subtracting the resting rate from your age-adjusted maximum rate. For example – your resting rate is 75 bpm, and your maximum is 175 bpm. Therefore your reserve heart rate will be 100 bpm. This is the figure we’ll use to find your optimal heart rate for each of the four zones.
What Does Age Have to Do with my Maximum Heart Rate?
Let’s begin with the basics; as a child, your heart was smaller than an adult’s. You also had a lower total blood volume (again, smaller body) and each time your heart beat it had to move less blood throughout your body. This is why children typically have higher heart rates than adults. As you age, your cardiovascular system will continue to change, and your working heart rate gradually slows down.
Origin of the 220 Minus Age Formula Came
It began in the 70s when doctors from the U.S. Public Health Service’s Program on Heart Disease needed a guideline for very sick heart patients to calculate their levels of exercise intensity.
The doctors never meant the formula they created to be used by the fitness industry.
But, it was an easy to remember formula that anyone could quickly work out in their heads. For the past forty years, this method has been designed into heart rate monitors, plastered on gym walls, and written into almost every health-related textbook.
Why the formula should be Different for Women
Women are advised to use a slightly modified version of this calculation that is based on a sixteen-year study that tracked women exercising on a treadmill.
Researchers concluded that women were at a higher risk for cardiac events when working out using the old maximum heart rate calculations. The advice for women according to this research is to instead subtract 88% of your age from 206 and try to keep within 65 to 85 percent of your maximum heart rate (MHR).
Optimal Fat Burning Heart Rate
First, we’ll calculate the optimal heart rate to stay in the fat-burning zone; there is both a high and low number which will represent your fat-burning range. One caveat; we burn fat in each of the four zones – but the fat burning zone is the heart rate range where you want to be to maximize your workout efforts for fat loss.
Start by dividing your reserve heart rate in half, and then add that number to your resting heart rate to discover the lowest bpm to enter this zone.
Then calculate what is 75% of the reserve heart rate, add it to the resting heart rate figure, and you’ll have the highest heart rate you can maintain and still stay in the Fat-Burning Zone.
Here are the calculations written out in an easy to use formula – just plug your numbers in to get the right answer:
- (Reserve HR x 0.5) + Resting HR = Lowest HR of the fat-burning zone
- (Reserve HR x 0.75) + Resting HR = Highest HR of the Fat-Burning Zone
The Aerobic Zone
Next, we’ll find out what your ideal heart rate range is for aerobic conditioning – you’ll stay in this heart rate range if your goal is to develop greater aerobic endurance.
Find 75% of the reserve heart rate you already calculated and then add it to your resting heart rate to learn what the low end of your aerobic zone is. Next, figure 85% of your reserve heart rate and add it to your resting heart rate. This number is the highest heart rate you can maintain and stay in your Aerobic Zone.
Here are the formulas to make calculations easy:
(Reserve HR x .75) + Resting HR = Lowest HR to stay in the aerobic zone
(Reserve HR x .85) + Resting HR = Highest HR to stay in the aerobic zone
This is the range where you’ll be pushing yourself out of your comfort zone; the aerobic/anaerobic threshold, alternately called the lactate threshold. This is the range most important for improving your athletic ability.
We find the heart rate range for this zone by taking 85% of the reserve heart rate and then adding it to the resting heart rate to get the lower end of this zone. To get the higher end, you’ll need to calculate 90% of your reserve heart rate and add it to the resting heart rate figure.
Use this to make it easier:
- (Reserve HR x .85) + Resting HR = lowest heart rate to stay in the Aerobic/Anaerobic Zone
- (Reserve HR x .90) + Resting HR = highest heart rate to stay in the Aerobic/Anaerobic Zone
The Anaerobic Zone Range
This is when you’re pushing yourself to the utmost. In this zone your heart is pounding, your lungs are on fire – and seconds can seem like hours. But, this is the all-out effort needed to best build your anaerobic ability (running, biking or swimming sprints). You might as well call this the red-line zone.
This time we’re taking 90% of the reserve heart rate figure and then adding it to our resting heart rate to find the lowest end required to stay in this zone.
Finally, take your reserve heart rate number and add it to your resting heart rate do this to get the highest heart rate you can achieve to stay in the anaerobic Zone.
One last time; two easy formula you can use to make the calculations:
(Reserve HR x .90) + Resting HR = lowest HR of the anaerobic zone
(Reserve HR x .100) + Resting HR = highest HR of the anaerobic zone
If you like to try an alternative formula to calculate your MHR, you can try taking 70% of your age and then subtract that number from 208.
This is a formula developed by Dr. Douglas Seals and first published in 2001. It calculates a much higher MHR for seniors.
Of course, if you prefer to avoid any math – you can also measure your work level by these simple rules of thumb:
- At moderate intensity, you can speak comfortably, but not sing
- At high intensity, you should be able to talk briefly without gasping for breath.