HR (HEART RATE) TRAINING ZONES: Have you heard of HR training zones?

When undertaking training for any endurance activity (running, cycling, triathlons, etc), there is a way to guide your training based on heart rate monitoring as a proxy of how intense you are training.

There is direct relationship between heart rate (HR) and training intensity, meaning as we exercise harder in a training session (increasing intensity), the HR will increase in direct proportion to our increasing speed/ pace/intensity.

HR zones therefore are a physiological based guideline of how easy or how hard we are training. The HR zones are made and based using a percentage of your maximum HR.

Instead of training guided by pace, you will monitor your HR to train and work at a specific effort.

Why training by heart rate (HR)?

HR based training will allow you to train at the right intensities to develop your aerobic system which should be your ultimate aim given this is the dominant system use to perform our best in endurance events.

Instead of training every time as hard as you possibly can (which is not the ideal way to train), HR training allows you to monitor your effort and train easy on easy days and harder on hard days (as this combination and balance between easy sessions and hard sessions has been shown to be the best model of training in endurance).

How we find our heart  rate (HR) zones?

HR zones are based on your maximum HR (the highest HR you see using a heart rate monitor when you train quite hard). Therefore, you will need a HR monitor (preferably a chest strap which research shows is more accurate than wrist based HR monitors on your GPS watch).

There are different ways to work out what your max HR (MHR) is. These can include:

1. The most accurate way is by doing an incremental exercise test, (or VO2 max test) in an exercise lab or a Physio practice. You are put on treadmill or a bike to exercise from an easy effort to hard one. The test protocol usually consist in running or cycling to incremental speeds every few minutes while using a HR chest strap (and a mask) until exhaustion. By the end of the test when you are “exhausted” unable to run or cycling further you will have reach your MHR.

2. Field Test : If you do have access to a HR monitor and already do some hard training sessions, you can track what your MHR has been in those intense workouts. If you are just starting running or cycling, do your own test either running outside, on a treadmill or on a bike (supervised and making sure you don’t have any medical conditions that restrict you to do a hard or intense exercise test). Usually running as hard as you can for few minutes (3-5 min), 2-3 times with a minute of rest in between until reaching exhaustion will give you the highest HR reading (MHR).

3. MHR Formulas: there are several formulas out there (Gellish 2, Fairburn, Tanaka, etc) to try to calculate MHR (and is not 220-your age) that are based mainly on our age. However, these still can be quite inaccurate and are only a rough estimate, as MHR differs between individuals of same age quite widely.

Be aware, MHR is lower as we get older. Also remember HR can be affected by temperature, environmental conditions, stress, dehydration, etc.

Now we have our MHR, how do we work out the HR training zones?

The most common training zones methods used are either;  5 training zones, or 3 training zones.

The 3 HR training zones is the simplest and quite easy to use. But if you a more experienced endurance athlete then the 5 HR zone could be the most appropriate to use.

5 HR training zones:

Recovery Zone (Zone 1)= HR less than 60% of MHR

Easy Zone (zone 2)= HR between 60-75% of MHR

Moderate Zone (zone 3)= 75-85% of MHR

Hard Zone (zone 4)= 85-90% of MHR

Very hard Zone (high intensity or zone 5) = More than 90% of MHR

For example, if my MHR is 186, then these will be my 5 training zones:

Z1 = MHR x 0.6 = 111-112 beats per minute
Z2= MHR x (0.6-0.75) = 111-139 beats per minute
Z3= MHR x (0.75-0.85) = 139-158 beats per minute
Z4 = MHR (0.85-0.90) = 158-167
Z5 = >167 beats per minute

3 HR training zones:

Easy intensity Zone (Z1)= MHR 55-75 % MHR= eg HR102-139 bpm

Moderate intensity Zone (Z2)= MHR 75-88% MHR= HR 139-164 bpm

High intensity Zone (Z3) = MHR >88% MHR= HR > 164 bpm

How to put the training together based on HR training zones

Most research suggest that best way to programming endurance training is combining larger volumes (around 80-90% of our training hours or sessions) of easy intensity zone training (zone 1 and 2 in the 5 zones model or zone 1 in the 3 zones model) with careful use of high intensity interval training (HIIT) Around 10-20% of training hours or sessions, zone 4-5 in the 5 zone model or zone 3 in the 3 zone model. Very small overall percentages of time should be spend training in the moderate zones.

For example: If I train 10 hours per week, around 8-9 hours should be dedicated to run in an easy intensity zone and the rest in runs that involve HIIT sessions or tempo/thresholds runs for example.

Several studies show remarkable consistency in this training distribution between best performers. This pattern has emerged possibly because this is the best distribution to stimulate a constellation of training adaptations or changes required for maximal endurance performance.

Larger volumes of training in the easy intensity zone is optimal to maximise adaptations like increase capillary vessels, increase mitochondrial density and size, development of slow twitch muscle fibres, increase enzymes associated with oxidative processes, increase capacity to use fat as energy, engrain correct repetitive motor pattern which all improve development of endurance.

Relatively small volumes of HIIT fulfil the need to optimise signaling for enhanced cardiac function and buffer capacity as well as some common effects as low intensity training (although by a different cascade or pathway).

If you have any questions regarding heart rate training zones please leave them below.

Guest Blog Post by

Medical Doctor with interest in Sports Medicine

Team Doctor for the AFWL Suns Team

Vast experience in Critical Care Medicine

Passionate Marathoner