How to read heart rate zones?

The graph below the key parameters provides an at-a-glance summary of the training. This depends on the maximum heart rate of each horse that can be set.

Heart Rate zones

For each training, EQUIMETRE calculates the time spent in each heart rate (HR) zone. These heart rate zones are based on the maximum heart rate (max HR) of each horse. They are therefore not the same for all horses and designate levels of intensity in relation to the maximum intensity level of the horse that is reached at its maximum heart rate. 

By default, the graphs do not take into account the time spent walking and inactive. If you choose to check the box to include inactivity and walk, these periods will be included and you will see Zone 1 Endurance take on a much greater importance.

The max HR is specific to the physiology of each horse, it evolves little and decreases slightly with age. It is in no way correlated with performance. 

How to read HR zones?

Zone Indications % HR Max
Endurance A light warm up. 0-60%
Moderate A light, aerobic training rhythm during which all lactic acid is eliminated and recovery processes are improved. It improves basic stamina and is mainly used in strengthening. 60-70%
Tempo Moderate training rhythm, mainly aerobic, during which lactic acid intervenes little. It improves endurance and develops the cardiovascular system to improve the use of oxygen. 70-80%
Threshold Intense training rhythm, anaerobic, enhances tolerance to lactic acid, which delays the onset of fatigue during a race and therefore contributes to the horse's stamina.  80-90%
Anaerobic Intense training rhythm, anaerobic, improves sprinting speed and neuromuscular coordination at racing speed. This work must be carefully controlled in case of extreme fatigue. >90%



  • Aerobic: the body uses oxygen to break down fat and produce energy without lactic acid ➡️ efficient mechanism until reaching maximum respiratory capacity where no additional oxygen can be assimilated (around max HR)
  • Anaerobic: the body breaks down sugars in the muscles ➡️ efficient mechanism for producing energy, but produces waste products, lactic acid, which the oxygen flush out
  • When the effort is very intense, lactic acid causes pain in the muscles. Lactic acid is evacuated by the oxygen brought by the blood. The heart and respiratory rates remain very high even after the end of the effort: this can be referred to as oxygen debt.

To find out more ➡️ Some physiological landmarks

How to set up the max HR?

The max HR of each horse is adjustable from the horse profile. It is calculated automatically with the max HR of the last intense training sessions of the horse on the last 6 months (less than 38s on 3 furlongs). By clicking on Edit, a pop-up window opens. 


You can select the max HR from a previous intense training (less than 38s on 600m in the last 6 months) or enter a value manually. 

Once this value is chosen, you can decide to apply it retrospectively and all the affected HR zone graphs will be recalculated accordingly.

If you have had a horse for more than a year, for example, you can adjust its max HR, but there is no need to apply it retrospectively since the previous year's work took into account a potentially higher max HR.

To learn more about the analysis of the heart rate and recovery, read this article.