Endurance training zones – intensity in training

Training intensity, or the measures of, can be hard to grasp. What is the lactic threshold, and how do you use the knowledge of different training measurements to build your training sessions? In this article about training zones in endurance sports, we will talk about what they are, how to measure them and what they mean. 

5 steps to successful training and racing

In order for you to juggle everyday life and to succeed with your training and racing, we have developed five steps, this being the last step. We will help you to define your starting point, your goal and the required training effort. We help you to answer how much, how often, and how hard you should workout. All of this is put together in an individual endurance training program.

In this series of articles, we will walk you through, 

  • How to start endurance training. With the knowledge of your mental and physical ability, you have a better chance to plan your season. We go through how you can make a self-assessment of your starting point.
  • Endurance training and racing. Your training season will “revolve around” the main race. So, how do you identify it, and what are your training objectives?
  • Training volume in endurance sports. Your capacity is slowly but surely built up during the season by a series of training sessions. Hours spent on training is, therefore, a central theme. How much and how often should you workout?
  • Endurance training plan – How to periodize training. Again, it is not only about training but also about training with a purpose. This is where the individual plan, with the different phases, comes in. When do you train what?

Intensity can be measured by the following

Perceived effort

Perceived effort is often measured by the Borg-scale and can be hard to define. For example, if you are training with a group, it is easier to get dragged into the “group psychosis”, and go with the flow of the group. But, if you don’t have a heart rate monitor, tempo or power meter. Then this is your best option. 


The tempo is the value of speed over a distance. It can be minutes per kilometer in running, time over 100 meters in swimming or kilometers per hour in cycling. This can be a good way of keeping track of your training, but it doesn’t take into account your form for that specific day. Say that you usually run a 10k in 45 minutes, which gives you a kilometer pace of 4:30 per kilometer. And some days, that tempo will be as tough as your usual time splits over a 3k run. You are not suddenly out of shape, but your body is trying to tell you something. Maybe you have had a bad sleep, or you are maybe getting sick? 


Measuring power is mostly associated with cycling. Though we are seeing a rise of power meters for running, and power meters for swimming exist, but are rare. Your power is measured in watts. Watts is energy over time, fun fact: 1 horsepower is 735 watts. 

Heart rate

Heart rate is probably the most used and applicable term of measuring your training. And what we use most in our training. Your max heart rate is genetically defined, and thus you can’t do anything about that. But you can lower your resting heart rate, and push your threshold heart rate closer to your max. The lactic threshold is a term used for the level of intensity where your body no longer transport the lactic acid away from your muscles. 

Understanding how you measure function and intensity is crucial for understanding how hard you should train. 

Using tests to define training zones

To understand where your threshold is, you can do tests. And in our training programs, we regularly do tests in all sports. This is because your functional threshold is sport-specific. 

We take test values from

  • Swimming – Time/100 meter
  • Cycling – Heart rate or power
  • Running – Heart rate or tempo

You can’t do one test that defines your functional threshold for all sports. In swimming, you will not be able to get the same puls as in running or biking. And your power on the bike is not applicable to your running. That is why you need to do tests sport-specific. 

When you have your test scores, it is time to look at what intensity you should train at. 

You will train in zone 2 for the majority of your training volume. Up to 80% of your training. With the remainder divided by zone 3-5. Zone 5 being around 5 – 15 percent depending on where you’re at in your season. 

Training in lower zones will give you effect over the whole spectrum

Training in zone 2 and zone 3 will push your functional threshold upwards. This is because of the work done in the lower zones, will widen your range of those zones, and that will help to push your zone 4 upwards. 

When doing your training plan, you need to focus on these statistics. If you are unsure about anything in the top end of the zones. It is our recommendation that you focus on zone 2 and zone 4. That will be the most beneficial.

To conclude, your training zones are individual, and not applicable to others. Therefore you need to keep track of your own progress and don’t follow any other persons training zones. 

  • Background

  • Training

  • Enter the date you think you are ready to start with structured training.
    Date Format: YYYY dash MM dash DD
  • A rule of thumb: Sprint (6-10h), Olympic (8-12h), Ironman 70.3 (8-14h), Ironman (10-14h)
  • Racing

  • If you have not yet decided, enter an approximate date.
    Date Format: YYYY dash MM dash DD
  • Other


Start typing and press Enter to search

Putting up a training goalHow to plan your season and training