Today we’re looking at an important tool we should be taking into account: heart rate when training.
What is heart rate?
Heart rate is one of the most relevant physiological variables when determining the intensity of exercise.
The number of heartbeats in a period of time, usually 1 minute.
Our heart rate shows us the state of our body in terms of the number of beats in that time period.
In relation to physical exercise and training, it’s a tool for control and programming for sessions and recovery.
What is it used for?
Not only will it help us determine our heart rate range when training, depending on the type of training (training zones – exercise intensity), it will also allow us to gain control before, during and after to adapt our training and not overreach our limits.
Training with heart rate zones
One the greatest problems found, for example, by popular athletes, is a total lack of knowledge of training zones in relation to heart rate, and their Ventilatory Threshold 1 and Ventilatory Threshold 2 values (commonly known as anaerobic threshold, but that name is inaccurate).
In this way, the tendency is to carry out training in high training zones, not giving rest to the different systems either to adapt or to recover and, therefore, the improvements sought tend to take longer to arrive and the athletes are generally more trained (although we don’t think this is the case).
In endurance sports, regardless of the variable we use to establish the intensity criteria (for example, power training in cycling), everything is determined by heart rate ranges and distribution or participation of the different metabolic pathways.
But, what are the heart rate zones for training?
The training zones are the established individualised ranges to which the body responds depending on an intensity, load (external or internal).
There are different models depending on the author: we can find models with 3 zones, with 5, and even with 7.
However, all its authors agree that the delimitations between one training area and another occur when there is what they call a Physiological Milestone:
When there’s a change in our body, a response; for example, lactate production, pulmonary ventilation, oxygen consumption, and, also, heart rate.
Let’s take a simple example
Imagine walking at a brisk pace, but you feel that you have perfect control over your breathing. It is not agitated, you can talk, sing and you could spend hours doing the same activity, and even (in highly trained athletes with a good aerobic base), do a very light jog with the same sensations.
Imagine now that you want to pick up the pace, you start jogging and you feel your breathing become more agitated, and even some hyperventilation and slightly higher heart rates.
This first change would be a physiological milestone that would mark you to move from an activation zone to a slightly more intense one.
It’s very important that you know that this is entirely individual.
What are the heart rate zones?
As I mentioned earlier, there are different distribution models of Training Zones depending on your heart rate, although the most used and basic model is the Tri-Phase Model of Skinner and MC Mellan (1980):
The model is the most used and shows 3 phases and 2 inflection points (2 physiological milestones) that mark the change from one phase to another.
These tipping points are the thresholds: aerobic (lactic) and anaerobic (maximum oxygen consumption).
This model divides the training zones in 3:
- Phase I: Aerobic.
- Phase II: Aerobic-Anaerobic Transition.
- Phase III: Metabolic Instability Phase.
Phase I: Aerobic Phase
Starting from rest to that first aerobic threshold.
The main energy pathway is the fat oxidisation pathway. Exercise intensity is very low and subjective perception of exertion is relatively low.
In terms of Oxygen (VO2), this will increase as our body needs more oxygen for the activity that’s being carried out.
In the first threshold, use is made of between 60% – 70% of the person’s maximum oxygen consumption.
As energy requirements increase (producing it more quickly), other energy production mechanisms will be activated; in addition to the oxidative pathway, the body will begin to use anaerobic glycolysis, with lactate appearing for the first time (hence the lactate threshold).
Phase 2: Aerobic-Anaerobic Phase
Starting at that threshold and ending at another physiological milestone, then around that lactic threshold and finishing at the next important turning point, which would start PHASE 3.
From this moment, in which the intensity increases progressively, the metabolism of carbohydrates (glycogen deposits) is required in addition to the oxidation of fats.
Thus, as we move towards zone 3, the use of sugars (energy requirements are more immediate) to the detriment of fats is gaining prominence.
The perception of effort gradually increases, and the sensation of working at a more demanding pace as well: from soft-moderate to hard-intense.
Oxygen consumption will also increase (up to 80% – 90%, which is when Phase III will begin).
Phase 3: Metabolic Instability Phase
This phase, erroneously referred to as anaerobic, is a “Metabolic Instability” phase, i.e. the need for energy and waste products resulting from the combustion of HCO is not going at as fast a rate as energy needs.
For this point of intensity, exercise can only be maintained for a very short period of time.
At this point, pulmonary ventilation increases again (hence the designation ventilatory threshold 2 VT2).
We would establish the heart rate zones for training based on this model, usually in a model of 5 training zones.
|Zone||Heart Rate||What happens?|
|Zone 1||<65%||Prepares your body for exercise and accelerates recovery.|
|Zone 2||65-80%||Optimises oxidative metabolism.|
|Zone 3||81-85%||Improves aerobic fitness and cardiovascular performance.|
|Zone 4||86-90%||Develops aerobic capacity.|
|Zone 5||>90%||Improves your short, high-intensity anaerobic performance.|
How do you calculate heart rate for exercise?
The only accurate, reliable and individualised way to calculate training zones based on heart rate is to perform a medical stress test with gas analysis.
From all the variables measured in the test (heart rate, respiratory ratio, pulmonary ventilation, oxygen consumption, blood pressure…), the values of all the variables are clearly determined, with determination of the 2 thresholds, maximum oxygen consumption.
Knowing your thresholds, you can now clearly, accurately, and individually determine training zones.
Another formula that is often used, also with some limitations, but perhaps a little more accurate and well-known, is the Karnoven formula (also an estimation):
- Maximum Heart Rate (MaxHR) = 220- Age.
- Reserve Heart Rate (HR) = MaxHR – Resting Heart Rate.
- Target heart rate Intensity at x % = (Reserve HR) * x % + Resting heart rate.
Calculate your Maximum Heart Rate
As I mentioned earlier, an increasing medical stress test on a treadmill or cycle ergometer is the best way to know what our maximum heart rate is.
Benefits of training with Heart Rate
As we have looked into in previous articles, knowing your training zones according to your heart rate ranges, sessions can be carried out according to the intensity set and not above or below it.
It’s true that, being a variable that’s affected by external and internal conditions (having been ill, environment temperature, humidity, among others), your heart rate may vary slightly, although you will be able to train within the established ranges depending on the intensity set by the training.
- García Pallarés, J., & Morán Navarro, R. (2012). Propuesta Metodológica para el Entrenamiento de la Resistencia Cardiorrespiratoria. Journal of Sport and Health Research, 119-136.
- López Chicharro, J., & Fernández vaquero, A. (1995). Fisiología del Ejercicio. Panamericana.
- What is Heart Rate Variability and what is its importance? Click here to find out everything you need to know.
- Why take a stress test? We give you our answer.