Comparative hematological and physiological responses to ground and pool training in Colombian Paso Horses.

Background and Aim: Exercise training causes physiological and hematological changes that are crucial for enhancing athletic performance in horses. While these responses have been extensively studied in various equine breeds, there is limited information regarding Colombian Paso Horses (CPH), especially concerning the comparative effects of different training methods. Ground-based training is frequently used to improve gait and speed, whereas aquatic exercise has become an alternative conditioning approach that lessens musculoskeletal stress. However, the physiological responses related to these training modalities in CPH are not well understood. Therefore, this study aimed to compare the immediate physiological responses of the hemo-leukogram, blood lactate levels, and heart rate in CPH undergoing ground and pool training. Materials and Methods: Ten clinically healthy CPH horses (6 females and 4 males), with an average age of 10 ± 4 years and a body weight of approximately 350 ± 20 kg, participated in this repeated-measures study. The horses performed high-intensity exercise on ground and aquatic training modalities, with a 30-day interval between protocols. Each session lasted 40 minutes and included warm-up, moderate-to-high-intensity activity, and a cool-down phase. Venous blood samples were collected from the jugular vein before and immediately after exercise to assess hematological parameters and blood lactate levels. Heart rate was continuously monitored using a heart rate monitor. Data were analyzed using either parametric or non-parametric statistical tests, depending on the distribution, with significance set at p < 0.05. Results: Both training modalities elicited significant post-exercise physiological responses. Ground exercise caused a notable increase in erythrocytes, hematocrit, lymphocytes, and globulins (p < 0.05). Pool training also led to significant increases in erythrocytes, hemoglobin, and hematocrit (p < 0.05). Blood lactate levels rose from approximately 1.04 to 5.80 mmol/L after ground exercise and from 1.29 to 2.46 mmol/L after pool exercise. Heart rate significantly increased in both methods, reaching about 203 bpm during ground exercise and 215 bpm during pool exercise. Long-term adaptations included a significant decrease in resting heart rate after both training protocols, indicating enhanced cardiovascular efficiency. Overall, physiological responses were more pronounced after ground exercise compared to aquatic exercise. Conclusion: High-intensity ground and aquatic exercises both induce significant hematological and physiological responses in CPH. However, ground-based training causes greater metabolic and hematological changes, indicating higher physiological demands. In contrast, aquatic exercise offers a lower-impact conditioning option that boosts cardiovascular efficiency while reducing mechanical stress. These findings emphasize the potential of integrating aquatic training into conditioning programs for CPH to improve performance and recovery.