The physiological responses to simulated race tests on a track and on a treadmill in standardbred trotters.

This research study compares the physiological responses of standardbred horses on a treadmill and on a track during simulated racing conditions. The study finds that the treadmill testing is similar to track racing when it comes to some physiological responses but does not fully represent the anaerobic metabolic response found in actual racing.

Methodology

• The study involved six Standardbred trotting horses in racing condition. These horses underwent two different tests – a standardised treadmill exercise test simulating racing conditions (ST) and a simulated race on a field track (FT).
• The researchers measured multiple physiological variables before and after the exercise, and during the recovery period. These variables included heart and respiratory rates, haemoglobin, packed cell volume (PCV), glucose, pH, total carbon dioxide and potassium levels in venous blood, and plasma lactate and total plasma protein levels.

Results

• The results showed no observable differences in heart rate, haemoglobin, PCV, total plasma protein, and glucose concentrations after exercise and during the recovery period between the two tests.
• Differences were, however, observed in plasma lactate – higher in the FT than ST. Moreover, total carbon dioxide concentrations and blood pH levels were lower at the end of exercise in the FT compared to the ST. These differences indicate greater anaerobic metabolism in the FT compared to the ST.
• Even 30 minutes post-exercise, plasma lactate concentrations remained higher in the FT. Blood pH returned to resting values at 15 minutes of recovery for the ST and at 60 minutes for the FT. At 60 minutes of recovery, total carbon dioxide concentrations had still not returned to resting values in either of the tests.
• The study also noted increases in blood potassium concentrations at the end of the exercise in both tests. However, these concentrations were lower after the FT compared to the ST.

Conclusion

• The study concluded that the haemodynamic response to the ST test at the end of exercise and during recovery, assessed by heart rate, haemoglobin, and PCV, was similar to the response observed in the FT test. The metabolic differences observed between the ST and FT show that the FT test, which includes a finish at maximal speeds, induces greater anaerobic metabolism.
• Thus, while the treadmill test used to simulate racing conditions does resemble the real-world haemodynamic response, it does not fully replicate the anaerobic metabolic response observed after a simulated race on a track.