You may hear a BitGym coach say "These hill sprints should get you to 70% of your maximum heart rate".
What is my maximum heart rate?
Maximum heart rate (MHR) varies from person to person, and isn't strictly defined. It's a heart rate caused by exertion levels that you cannot sustain for more than a minute.
Calculating my Max Heart Rate
Here is an easy-to-remember formula to ‘estimate’ your heart rate.
MHR = 220 - your age beats per minute (bpm)
If you are a 40 year old person (this equation is independent of gender), and you are intstructed to exercise on the treadmill at 60-80% of your MHR ability.
According to the equation, your max will be 220 – 40 = 180 bpm.
In theory, this means that a 40 year old heart will beat a maximum of 180 times in a minute, if the person exercises exercise as hard as they can. This is your MHR.
Since, in this example, you want to exercise at 60% and 80% of the maximum, the target bpm is calculated this way:
180 X 0.6 = 108 bpm and 180 X 0.8 = 144 bpm
Tip: to change a percent to a decimal, just move the decimal point two places to the left. Hence, 60% becomes 0.6.
To follow these instructions, you should keep your heartrate between 108 - 144 bpm
A more accurate formula would be:
206.9 – (0.67 X age)
The ACSM (American College of Sports Medicine) says this formula is “the most accurate” of the various maximum heart rate equations you may have heard of. This formula looks a bit more complicated than “220 – Age” but it's not too bad. Let's take a look at it by keeping with our 40 year old person example from above.
206.9 – (0.67 X 40) = 206.9 – 26.8 = 180.1 bpm.
Keeping within 60%-80% will be 108.06 - 144.08 bpm. Notice that these numbers are practically the same as we obtained from the simplified formula.
Once your age gets a lot closer to 200, the accurate formula will be more necessary.
Stick with BitGym and maybe you'll have to switch to the more accurate formula :)