Training Zones (Intensity Zones)

The worldwide COVID19 pandemic has made people much more aware of possible underlying (and often hidden) health conditions. If you are over 40 and have been training and racing for many years, the chances are 100% that you know of somebody who died during training or racing.
Almost equally tragically, you may know of people who have done irreparable harm to their heart muscles because they trained with an underlying condition (like flu or a serious infection) without realising how serious it was.

Over the past three years, I have stopped myself no less than three times during training sessions because my heart rate was abnormal. This is an average of once a year! In two of those three cases, I did have an underlying condition that I was not aware of. Thankfully I stopped before doing any harm to myself. The third instance turned out to be a problem with a worn-out heart rate monitor strap.

The bottom line is this: By training hard, you are placing your body under significant strain. You should NEVER do this if you have an underlying infection or slumbering illness. In the vast majority of cases, using a heart rate monitor will help you to stay out of trouble – provided, of course that you listen to what the monitor is telling you!

There are two key metrics to track to make sure you avoid overtraining. The first one is your resting heart rate during sleep. Although it is common for your heart rate to vary during your sleep cycle, the lowest heart rate recorded during sleep is usually fairly consistent from one day to the next.

If this lowest heart rate value during sleep suddenly increases by more than 5 bpm, you need to be cautious. My suggestion is to adapt your training programme to make your sessions a little less intense – especially if the second metric (your resting HR during the day) is also elevated. A 5 bpm higher heart rate during sleep could indicate that you have not recovered sufficiently. If you carry on regardless, you risk overtraining, and you will have an increased susceptibility to catching a cold, flu or other infection.

The second metric is your general resting heart rate (during the day). Most smartwatches and fitness-specific devices will give you this information.

To summarise: You need to track your resting heart rate during the day as well as during the night when you are sleeping. Any significant rise in either of these resting heart rates signals caution.
If both are elevated by 5BPM or more, you absolutely have to adjust your training programme to allow more time for recovery.

I include some (of my own) examples below to illustrate this concept in a bit more detail.

This is the reason most people buy a heart rate monitor in the first place.
Unfortunately, many people use incorrect intensity zones.

Most companies (Polar, Garman, Fitbit, and others) have a standard formula to calculate intensity zones.
These intensity zones are designed for (and suitable for) “ordinary people”.
They are not optimal for competitive athletes who have been training (and racing) for many years.

You need to adjust the “standard” intensity zone calculation provided by these devices as follows:
You need to know your Resting Heart Rate (RHR).
I suggest taking the lowest resting heart rate during sleep for this value.

You need to know your Maximum Heart Rate (MHR).
Most likely, you already know your MHR.
If you do not know your MHR, you need to perform a maximum heart rate test. (The “standard” formula of using 220 minus your age is NOT good enough to determine your MHR).

Please note: If training at or near your maximum heart rate is not something you’ve been doing regularly over the last couple of months, you need to consult your doctor before proceeding to do this test. Please, rather be safe than sorry.

Given the people who are likely to be reading this, I do not expect that performing a maximum heart rate test will be dangerous for most of you. I presume that you often go near maximum effort (and therefore heart rate) during your training. If this is not the case, please take care and see your doctor before performing a maximum heart rate test.

Now that you have these two measurements (resting heart rate and maximum heart rate) determining your intensity levels is reasonably easy to do.

If you subscribe to my free email training course outlining the 6 Biggest Training Mistakes made be Athletes over 40 below, I will send you an Excel spreadsheet that does this for you. Then, you can simply plug these two values into the spreadsheet and the zones will be calculated for you.

The formulas used in the spreadsheet and how they are used is explained below.
If you don’t care about the calculation and want to simply use the spreadsheet provided, skip ahead to “Training activities in each zone below”.

Calculate your Adjusted Heart Rate Value (AHRV).
AHRV is just a term we will use to calculate your ideal intensity zones - nothing more.

Adjusted Heart Rate Value (AHRV) = Maximum Heart Rate (MHR) minus your Resting Heart Rate (RHR) AHRV = MHR – RHR.

I recommend that you use 5 Intensity Levels. (Most smartwatches and sport-specific devices make provision for five levels.).

The table below shows you how to calculate the Lower and Upper HR limits for each intensity zone.

Knowing what the correct Heart Rate Zones are is step 1.
Knowing what type of training you should be doing in each zone is step 2.
Knowing how much and when to do each type of training during the course of a year (or training season) is step 3.

Outlined below is a brief overview of the type of training you should do in each zone.
For additional information on the Training Types - please also refer to this page.

I have developed a unique Dial to help you better understand training zones, and how training at different intensities affects your body.
Using this Dial, the training zones are shown graphically below.

The 8 Training Types