Effects of training on cardiorespiratory function in the horse

Area of Science:

• Equine physiology
• Exercise science
• Cardiovascular research

Background:

• Cardiorespiratory function is crucial for athletic performance in horses.
• Understanding the effects of training on equine physiology is essential for optimizing performance and preventing injury.

Purpose of the Study:

• To investigate the impact of 5- and 10-week treadmill exercise training on cardiorespiratory parameters in horses.
• To assess changes at rest and during graded exercise up to 90% of maximal heart rate.

Main Methods:

• Horses underwent treadmill exercise training for 5 and 10 weeks.
• Measurements included cardiac output (Q), heart rate (HR), stroke volume (SV), left ventricular pressure (LVP), aortic pressure (AoP), right atrial pressure (RAP), peak first time derivative of LVP (LV dP/dtmax), oxygen uptake (VO2), and respiratory exchange ratio (R).
• Data collected at rest and during five exercise intensity levels.

Main Results:

• At rest, LV dP/dtmax was lower after 10 weeks of training.
• During exercise, cardiac output (Q) and oxygen uptake (VO2) remained unchanged.
• Significant reductions in HR and R were observed post-training, alongside trends toward lower LVP, AoP, and LV dP/dtmax.
• Stroke volume (SV) and mean right atrial pressure (RAP) were significantly elevated after 10 weeks of training.

Conclusions:

• Treadmill exercise training induces significant adaptations in equine cardiorespiratory function.
• Training leads to decreased heart rate and improved stroke volume during exercise.
• Elevated venous pressures during exercise suggest increased venous return or altered fluid dynamics post-training.