Plasma potassium and lactate concentrations in thoroughbred horses during exercise of varying intensity.

This study investigates how intensive exercise impacts plasma potassium and lactate levels in Thoroughbred horses, with the data suggesting that high-intensity physical activity could potentially disrupt neuromuscular function.

Research Methodology

• The subject group included 6 Thoroughbred horses.
• The horses exercised on a treadmill set at a 5-degree incline. The exercise routine included an 8-minute warm-up and then continued for up to 6 minutes.
• The horses exercised at different speeds—8, 9, 10, or 12 meters per second, and post-exercise, they walked on a 0-degree incline treadmill.
• Exercise sessions were ceased upon indications of fatigue.
• The researchers collected carotid arterial blood samples during and after the exercise.

Research Findings

• During exercises at 8, 9, and 10 meters per second, the potassium levels in horses initially rose, peaking after approximately 1.5 minutes of exercise. Afterwards, the concentration slowly declined.
• However, at 12 meters per second, a continuous increase in potassium levels was observed up to the end of the exercise period.
• Post work-out, potassium concentrations quickly (within 3-4 minutes) returned to levels recorded following the warm-up period.
• Plasma lactate reached its peak towards the end of the exercise, regardless of the exercise speed.

Interpretation of Findings and Conclusions

• The research demonstrated that during high-intensity exercise, the mechanisms responsible for potassium re-uptake in these horses’ bodies could not effectively cope with the efflux rate.
• However, with less intense workouts, the rate of potassium re-uptake appeared to match or slightly exceed the efflux rate.
• The study suggests that an imbalance between potassium efflux and re-uptake during vigorous exercise could potentially disturb normal neuromuscular function in horses.