Last month we took a look at Heart Rate Zones (HRZs) with a description of each of the five training zones. This month we will delve into this topic a little more deeply and show how you can determine your own HRZs.

There are a number of ways to do this and we shall consider the two most popular methods: (apologies for the maths)

1. The first and easiest way is to simply work out your HRmax (maximum heart rate) using the following generic formula: 220 - age (in years). So in theory a twenty year old will have a HRmax of 200bpm (beats per minute) whereas a seventy year old will be 150bpm.  Now you can calculate the zones thus:

Zone 1 (50-60%): at twenty years of age is 50% - 60% of 200 = 100bpm - 120bpm

Zone 1 (50-60%): at seventy years of age is 50% - 60% of 150 = 75bpm - 90bpm

The other four zones can be calculated with similar calculations. This method is oversimplified, not taking into account fitness levels and sex. However for most people, the ease of calculation outweighs the slight inaccuracies.

2.  The second, more in depth method does take into your account resting heart rate (regarded as an accurate measure of your fitness). So now lets take a look at our two athletes again, whom both,  coincidentally have a resting heart rate of 50bpm.

First we need to calculate the heart rate reserve (HRR) for each. The HRR is your resting heart rate subtracted from your maximum heart rate and shows us the buffer range we have for exercise:

Twenty year old: HRmax 200 - RHR 50 = HRR 150

Seventy year old: HRMax 150 - RHR 50 = HRR 100

As we can see from these examples the twenty year old can increase his resting heart rate threefold before having to stop whereas the seventy year old only twofold.

More calculations I’m afraid, and we will use the twenty year olds data:

To work out the 50-60% zone we take into account the HRR.

Add 50% and 60% of HRR to RHR ie 50% and 60% of (150 + 50bpm)

75 and 90 added to 50 = 125bpm - 140bpm

If we do the same calculations to the seventy year olds figures we get: 100 - 110bpm

Hopefully you can see that by taking into account the resting heart rate we can calculate a much more accurate set of values for the zones (compare the bold figures in both examples).

If you are fairly new to exercise I would recommend using the first basic calculations as they are still very good and easy to work with. As you advance your training perhaps you might consider using the second method and recalculating your zones for more effective training.