Responses to training and standardised exercise test in the athlete horse: changes in blood gas profile

In order to assess the relationship between blood gas profile and athletic performance after a specific training programme, six clinically healthy Italian saddle horses were used. Each animal was subjected to an adaptation period constituted by horse walker exercise, followed by a training programme for 3 months. In the last day of each month, all horses were subjected to a standardized exercise test (SET), consisting of 15 min of treadmill. On blood samples collected by means of a jugular venipuncture at rest, immediately after each SET and after 15 min, pH, partial pressure of carbon dioxide (pCO₂), partial pressure of oxygen (pO₂), haematocrit (Hct), haemoglobin (Hb) and hydrogen carbonate ion (HCO₃ ⁻) were assessed by means of a selective ion analyser. Two-way repeated measure analysis of variance, followed by Bonferroni's test, showed a significant effect of training on pH, pO₂, pCO₂, Hct and Hb. No statistically significant differences were observed among SETs 1, 2 and 3. Our results showed that physiological alterations in blood gas profile due to training exercise are common in horses. These changes are useful to assess the current status of an athlete and the degree of training adaptability, providing an opportunity to modify the training schedule accordingly to achieve the desired performance.