Your new training partner – The Heart Rate Monitor

There is much debate as to the use of heart rate monitors in triathlon – what heart rate should I train at? For how long? When should I ease back? When should I push on harder?


Triathletes are a competitive bunch by nature and for many that translates into hard work, will power, and a determination to succeed. Unfortunately these attributes very often lead to over training and poor performance. If racing success was judged on the efforts put into training alone, we would see the vast majority of triathletes achieving faster times in each race – not always the case!

Many triathletes train at too high a heart rate for too long a duration and often at the wrong time of the season. For many there is a belief that the only way to race faster is to train faster. This is simply not true and will lead to burn out and in many cases injury.

Many people own a heart rate monitor but choose not to use it because they don’t fully understand how to use it effectively. We want to change that right now! We advocate the use of heart rate monitoring and have designed all our workouts around specific heart rate training zones to maximise effectiveness of your training and ensure that you reach your peak levels of fitness at the right time of year.

When you become an athlete with, you will be provided with 4 heart rate training zones:

  • Zone: 1 – Extensive Aerobic Zone
  • Zone: 2 – Intensive Aerobic Zone
  • Zone: 3 – Threshold Zone
  • Zone: 4 – Speed Zone

Training in Zone: 1 and Zone: 2 – The Aerobic Zones

Triathlon of any distance is an endurance event in which the body burns a combination of carbohydrate and fat to fuel the sustained and continuous muscular work of swimming, cycling, and running. For the muscles to produce energy in this way they require a continuous supply of oxygen via the lungs, heart and blood stream.

Fat is stored by the body in relatively large amounts in a layer underneath the skin called adipose tissue:

  • A typical 60kg female athlete with 20% body fat will have 12kg (12,000g) of fat stored on her body.
  • In each 1g of body fat there are 9kcal of stored energy
  • This means that there is approximately 108,000kcal of energy stored as fat(12,000g x 9kcal), enough to complete 15 ironman triathlons.
  • In contrast, this same athlete will have much smaller reserves of carbohydrate stored on her body. Assuming her carbohydrate intake is optimal:
  • Approximately 100g of carbohydrate can be stored in the liver and 300g stored in the muscle
  • In each 1g of carbohydrate there are 4kcal of stored energy
  • Therefore, total energy stores of carbohydrate would be approximately 1,600kcal(400g x 4kcal)

Remember, for the body to burn fat for energy, it needs to be burnt alongside carbohydrate. Therefore, if your carbohydrate stores become depleted then your body’s ability to burn fat will be limited and your performance levels will start to drop. It would therefore make sense to train the body to become more efficient at tapping into its fat stores, and as a result, slow the rate that it burns up carbohydrate. To achieve this it is vital that a high volume of your training consists of workouts performed in training zones 1 and 2 (the aerobic zones).

Each week you will perform Extensive Aerobic Workouts in all three disciplines to improve your aerobic base and increase your body’s ability to burn fat for fuel. These workouts are the longest of each discipline that you will perform each week with the focus on keeping the intensity aerobic (enough oxygen is present to create energy from fat stores). For the majority of these workouts your heart rate will be maintained in zone 1 but will at times move into zone 2, particularly on uphill stages of your run and bike workouts. It is vital that you stick to the heart rate zones provided in these workouts as allowing you heart rate to exceed these zones will reduce your ability to build your aerobic base and improve your fat burning potential.

But that means I have to walk when I’m supposed to be running!!!!

In short – YES IT DOES!

This is the most common feedback we get from all our athletes.

There will be times when you may have to walk to prevent your heart rate exceeding the limit of your aerobic zone. Pick your route wisely, avoid too many hills where possible and when your heart rate tells you to walk – WALK! Many athletes find it hard to discipline themselves to do this, particularly if they’re used to working as hard as they can in every workout. However, to build your aerobic base, you need to train in an aerobic training zone. Enjoy this feeling, over time your workouts will become much tougher.

Training slowly will not make you race slowly! The more extensive aerobic work you perform the less you will need to walk. Over a period of weeks you will notice that you are able to run more at a lower heart rate and run faster with the same amount of effort. As your programme progresses and your aerobic base increases, these workouts will gradually increase in duration and you will be ready to begin some high intensity work and increase your heart rate into zones 3 and 4.

Training in Zone: 3 – The Threshold Zone

Your anaerobic threshold reflects your maximal sustainable heart rate. With any further increases in heart rate above the anaerobic threshold you would start to accumulate lactic acid rapidly in your muscles. When this happens you start to quickly fatigue, your legs start to feel heavy and ultimately, you have to slow down.

By performing workouts in the threshold zone, the heart rate at which your anaerobic threshold is reached will begin to increase. Over time, you will be able to work at higher heart rates for longer without the build up of lactic acid, therefore your maximum sustainable pace (race pace) will be higher. Your muscles will also become more efficient at tolerating lactic acid and removing it quickly. This will enable you to get back to your race pace quickly after running or cycling up a hill when your muscles will probably have began to accumulate lactic acid.

The heart rate that indicates your anaerobic threshold will be determined 12 weeks before your race. During this final stage of your programme you will perform a series of interval training sessions in which you will push the intensity up to and above this heart rate. Training in the threshold zone will feel very challenging and it is important that you have developed a good aerobic base beforehand.

Training in Zone: 4 – The Speed Zone

Training in the speed zone involves performing short, maximal intensity sprint intervals in which your heart rate will increase to near maximum levels. Speed training sessions will improve your capacity to accelerate, initiate a change of pace, and improve your race pace. Without speed, you will only have one pace and will be unable to perform significant changes in pace without becoming heavily fatigued. Again, these workouts will feel very challenging and to get the maximum benefit from them, you need to have a good base level of aerobic fitness.


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