The effect of sildenafil citrate administration on selected physiological parameters of exercising Thoroughbred horses.

The research investigated the impact of administering sildenafil citrate (typically used to treat erectile dysfunction) on physical parameters of thoroughbred horses during exercise. No significant effects were observed in terms of performance improvements or reduction of exercise-induced pulmonary haemorrhage. However, altered heart rates were found at sub-maximal speeds and post-exercise due to sildenafil.

Objective and Methods

• The aim of the research was to discern whether administering sildenafil citrate to horses during exercise made any difference in their performance indicators or reduced exercise-induced pulmonary haemorrhage.
• For their methodology, the researchers used two crossover design exercise testing studies in which they tested 13 thoroughbred horses. These horses were given either sildenafil citrate or a placebo.
• They performed various measurements such as an analysis of inspired/expired gas, blood lactate, heart rate, runtime, bronchoalveolar lavage (BAL) cytology, and pulmonary arterial pressure, during two exhaustive exercise tests.
• Data analysis was conducted using paired and unpaired t tests, one-way ANOVA, Tukey’s pair-wise multiple comparison, and Friedman repeated measure analysis of variance on ranks.

Results

• The researchers found that the administration of sildenafil did not alter mean inspired/expired gas measurements, plasma lactate concentrations or acute pulmonary haemorrhage in either of the exhaustive exercise tests. Also, there was no effect on the measurement of pulmonary arterial pressure in the trial where horses exercised at 13 m/s.
• The heart rates during submaximal speeds and during the early recovery period were significantly different in both trials after the sildenafil administration, indicating that sildenafil influenced cardiovascular adaptation to intense exercise.
• However, the runtime was not affected by sildenafil administration in either of the exercise trials.

Conclusion

• The study concluded that sildenafil citrate did not alleviate pulmonary haemorrhage or enhance performance-related indices in the exercise trials.
• However, sildenafil did alter heart rates at submaximal speeds and post-exercise, suggesting its potential influence on cardiovascular adaptation during intense exercise.
• The researchers state that the impact of these alterations on other performance parameters was not clear and would need further investigation.