Characterizing the Exercise Workloads and Energy Needs of Horses

The ability to accurately characterize a horses workload is an important part of management. This allows caretakers to provide enough calories and nutrients to ensure proper body weight and condition in their horses.
Just like humans horses require energy to power their muscles for movement. Energy is present in all feed for horses this includes grain hay and fresh pasture. Feeds with high amounts of fat starch and sugar provide the most energy. However unlike humans the horses digestive system also allows it to use a large amount of fiber for energy. Through metabolism the energy in the feed consumed is converted to energy that can be used for movement. For this to occur horses will need to be supplied with a certain amount of energy in their diet each day.

So how much energy is needed for horses that exercise? What about horses that are in intense or very heavy exercise compared to horses in light exercise? The National Research Council NRC has answered these questions based on previous equine research. The NRC published The Nutrient Requirements of The Horse 2007 which compiles research data and splits exercise workload into four categories Table 1 which are then used to determine a horses energy needs.  
Exercise Category
Average Heart Rate
Exercise Description
Types of Events
Light
80 beats per minute
13 hours per week 40 walk 50 trot 10 canter
Recreational riding
Beginning of training programs
Show horses occasional
Moderate
90 beats per minute
35 hours per week 30 walk 55 trot 10 canter 5 low jumping cutting or other skill work
School horses
Recreational riding
Beginning of training breaking
Show horses frequent
Polo
Ranch work
Heavy
110 beats per minute
45 hours per week 20 walk 50 trot 15 canter 15 gallop jumping other skill work
Ranch work
Polo
Show horses frequent strenuous events
Lowmedium level eventing
Race training middle stages
Very Heavy
110115 beats per minute
Varies ranges from 1 hour per week speed work to 612 hours per

week slow work
Racing Quarter horse Thoroughbred Standardbred endurance
Elite 3day event
Table 1 National Research Council Nutritional Requirements of the Horse 2007
Duration Frequency and Intensity of Exercise
When characterizing a horses workload caretakers need to think about the duration time spent exercising per week frequency how often a horse is exercised per week and intensity of exercise. The intensity of exercise refers to how hard the horse is working. This can be identified by the time spent at each gait. A horse that gallops for a certain amount of time will expend more energy compared to a horse that walks for the same duration of time therefore the exercise would