The Form - Heart Rate displays historical information for heart rate training zones for a horse. We break training work into heart rate zones, using the standard polar equine zone ranges:
Maximal : > 220bpm
Hard: 200-220 bpm
Moderate: 190-200 bpm
Very Light: 140-160bpm
The app displays time spent in the top three zones, Maximal, Hard and Moderate. We tend to find that a fit horse will show less time spent in the Maximal heart rate zone for a given work load vs an unfit horse performing the same work. As a horse progresses through weeks of training, if the workload was to stay constant, you'd expect the time spent in the maximal zone to decrease at the start of the traing and level off as the horses fitness increases.
Looking at these trends and knowing a horses workload can tell you whether the horse is coping with the training load, or can handle more, or perhaps needs a break to allow its fitness to build.