In today's Science Corner, we look at ways to monitor a horse's recovery after exercise, which is vital to knowing how fit and healthy our horse is, as well as minimising the risk of injury. How can we maximise that recovery, and how can we reduce the risks of horses incurring injury during exercise?
Each month, we break down five recently published scientific studies that could affect the way we breed, train, and race Thoroughbreds. We explain what the research found and what it means for you.
You can click the title of each paper to read it in full.
1. Exercise recovery includes affecting sleep too
What’s it about?
This study looked at what happens to sleep when horses exercise to different intensities. Horses were observed through the night to see how their sleep changed when they exercised more than their normal routine.
Horse sleeping | Image courtesy of Horse Sport
Key findings:
Across all exercise phases, horses spent most of the night awake, followed in quantity by sleep and rest.
Increased exercise led to longer bouts of sleep and rest, with sleep patterns remaining altered for a period of time even after return to normal exercise levels.
What it means for you:
Increased workload affects a horse beyond just the day and night after the period of exercise. This shines a light on the relationship between exercise and sleep in horses, and suggests that thought needs to be put into all facets of recovery after a harder work day, for example after a race.
2. Inflammatory markers take several days to recover after strenuous exercise
What’s it about?
This study looks at blood components in horses and how they respond to different kinds of exercise. Two groups of healthy horses were evaluated - one set undertaking a 2400-metre flat race and one set doing a 40km endurance race - and their blood was examined for indicators of the acute-phase response.
Key findings:
The endurance race induced a significant and time-dependent increase in inflammatory marker serum amyloid A (SAA) concentrations, with peak values observed at 96 hours post-exercise.
By contrast, there was no significant difference in the values of SAA, haptoglobin, or ceruloplasmin before or after the 2400-metre race.
What it means for you:
This suggests that exercise duration plays a key role in regulating a horse’s systemic inflammatory response. Monitoring these components of blood could be a useful tool for assessing recovery in horses. Given the stressors placed on a horse during long periods of transport, it could be useful for racehorse trainers too.
3. The unfit body consumes more fuel
What’s it about?
How can we tell just how tired a horse is after a piece of work? This study looked at blood metabolite profiles, performance, and body temperature after exercise to define levels of exhaustion in equine athletes.
Key findings:
Training improved gallop times, the amount of energy used, and the body temperature post-standard exercise test. Plasma lactate and creatine kinase increased post exercise and took 6-24 hours to return to baseline.
In unfit horses, muscle glycogen content decreased 24 hours after exercise, but improved with conditioning, while plasma alanine increased in the hour post exercise, suggesting use of alternative fuel for cells.
What it means for you:
The exhausted horse uses a greater amount of amino acids and beta-hydroxybutyrate ketones after exercise than the fit horse, underlining the need to support horses in the early stages of training as they rebuild fitness. This also opens the door for specific research on how exercise in horses affects tissue and muscle repair.
4. Most horses who experience proximal sesamoid and condylar fractures are high risk at previous starts
What’s it about?
Proximal sesamoid and condylar fractures can frequently be catastrophic, and it is in the best interests of all horses to look deeper into early identification of these injuries. This study retrospectively looked at data from inertial sensors to identify trends in at-risk horses.
Proximal sesamoid fracture | Image courtesy of AO Foundation
Key findings:
Fracture-specific algorithms examined accelerometer data from 42,623 races by 15,755 horses, including 144 races by 54 horses that subsequently suffered either kind of fracture.
Eighty-nine percent of the fractures occurred in the group of horses designated as high risk by the sensor data. Greater than 98.8% of horses with a risk score under 5 (high risk) did not suffer either fracture type.
What it means for you:
The vast majority of horses who have a proximal sesamoid or condylar fracture show some signs that this is going to happen in previous starts. This indicates that further study on sensor data would be useful to ascertain the movement and speed patterns that indicate a horse is high risk, then research can be done into how to implement that into everyday training and racing.
5. Horses who start earlier, race better
What’s it about?
The merits of 2-year-old racing continue to be debated, and this study aims to add to the body of work that ascertains whether or not it should continue. This study retrospectively analysed the careers of 600 Thoroughbreds based on the lengths and heights of their careers to see if start time has an effect on a horse’s career.
Key findings:
Sex clearly influences career length; geldings had the longest careers as they did not go to stud.
Geldings that entered training earlier and having their first race at two had higher race ratings than others, and there was no significant difference in career length to geldings who started racing later.
What it means for you:
This study ratifies other findings that starting racehorses early is better for them, or at least is not detrimental in comparison to starting them later. Further research is needed to look into the reasons why different racing careers end, and if there is any correlation between age and performance with each of those.
