Training Young Warmbloods: What New Heart Rate Research Shows

A young Warmblood's first serious season is usually described in the language of activities: so many days on the lunge, a few sessions down the free jumping chute, time on the walker after the farrier has been. Very few barns describe it in the language of load. A study published on October 19 in the journal Animals suggests that the activity labels are a poor guide to what a three-year-old is actually spending.

The research comes from Mendel University in Brno, in the Czech Republic. Daniela Kacetlová and colleagues at the university's Faculty of AgriSciences monitored the heart rates of 14 three-year-old Czech Warmblood stallions through an 18-week standardized training program. Across 1,003 recorded sessions in six exercise modalities, the team logged mean, peak, and minimum heart rate for every session. They then estimated daily energy expenditure two ways: with heart-rate-based equations, and with the recommendations of the National Research Council.

What the Monitors Recorded

The type of exercise was associated with both mean and peak heart rate (p < 0.001 for each), though not with minimum heart rate. The week of training mattered as well, for all three measures. When the team modeled energy expenditure per session, the highest values came from free jumping and from the horse walker. The lowest came from lunging.

Free jumping and the walker, two sessions easily filed under light work, produced the highest estimated energy cost per session in the study.

That result needs a careful reading. A per-session figure combines how hard the horse worked with how long it worked, and the authors conclude that training load should be assessed by both the characteristics of the exercise and the duration of the session. The numbers describe what the horse spent across a session, not how demanding any single minute was. That is precisely the point. The name of an activity says very little about its cost.

The Feed Chart and the Heart Rate

The second finding goes straight to the feed room. Estimates based on the National Research Council's recommendations put daily energy expenditure at 113.87 MJ (27.2 Mcal). The two heart-rate-based Coenen methods produced 100.33 MJ (24.0 Mcal) and 95.78 MJ (22.9 Mcal). Worked out from those published means, the NRC figure ran about 13.5 percent above the first heart rate estimate and about 18.9 percent above the second.

The authors decline to call either number correct, and their caution deserves respect. They state plainly that energy estimates derived from heart rate should not be regarded as independently validated measures of a horse's energy requirements. The National Research Council's Nutrient Requirements of Horses, published in its sixth revised edition in 2007, is a reference written primarily for nutritionists and veterinarians. What the gap does establish is that a ration built from a table and a ration built from the horse's own data can differ by a meaningful margin. For a growing three-year-old, that margin is an argument for the weight tape and a regular body condition score, with the chart as a starting point rather than the answer.

The Case for Early Work

None of this is an argument for doing less with young horses, and the strongest evidence points the other way. In a 2021 review in Animals, Alyssa Logan and Brian Nielsen of Michigan State University evaluated the epidemiological and physiological literature on training two-year-old racehorses. They concluded that horses trained or raced at two had a lower risk of injury and tissues better adapted to the demands of racing. The same review warned that the widespread use of pain-mitigating substances in racing places horses, young ones included, at greater risk of injury.

Researchers at Mendel University have also shown that a structured program can be well tolerated. In a related study in the Journal of Equine Veterinary Science, the group followed 13 Czech Warmblood stallions through 112 days of preparation for breeding licensing. Heart rate and lactate during standardized free jumping stayed stable throughout, which the authors read as an appropriate aerobic workload, and they observed no markers of muscle damage or chronic stress.

The case for early work stands. Its premise, though, is that the work is dosed, and a dose requires a measurement. Both Brno studies could reach their conclusions only because every session was monitored.

What the Young Horse Test Cannot See

The sport's main instrument for judging young horses measures something else entirely. At the Swedish University of Agricultural Sciences in Uppsala, Bonow and colleagues linked young horse test assessments with insurance records for 5,991 Swedish Warmbloods born between 2010 and 2020. In their Equine Veterinary Journal paper, published online in September, only 11 of 48 linearly scored traits were significantly associated with orthopedic diagnoses. A high score for trot at hand was linked to lower risk in both jumping and dressage horses, and greater height at the withers to higher risk. The authors concluded that the traits currently assessed have limited value as indicators of future orthopedic health.

A young horse test grades the horse that arrives on the day. It keeps no record of the weeks of preparation that brought it there.

What Buyers Should Ask For

The position here is straightforward. Young sport horses should be trained, and their training should be recorded in units of load as well as in days and activities. The Brno team collected its data under field conditions, across more than a thousand sessions, which answers the objection that this kind of record belongs only in a laboratory.

For a buyer looking at a three- or four-year-old, that suggests better questions than how high the horse jumped down the chute. How many free jumping sessions has the horse done, and how long did each one last? How much time does it spend on the walker? Was any of the work monitored? A seller who can answer with numbers is offering something more useful than a video.

For an owner bringing a young horse along, the walker result and the feed result lead to the same habit. The label on a session and the figure on a chart are both approximations. Log the work, weigh the horse, and let the record decide what counts as an easy day.