Pulmonary artery wedge pressure increases with high-intensity exercise in horses.

This study explores how intense exercise in horses can considerably raise their pulmonary artery wedge pressure, heart rate, and other related cardiovascular variables.

Methodology

• The researchers used catheter-mounted microtip manometers to measure numerous cardiac variables like right atrial pressure, pulmonary artery pressure, and pulmonary artery wedge pressure.
• The study was carried out on eight horses which were observed during rest, as well as during various intensities of exercise on a treadmill with speeds of 8, 10, and 13 m/s.

Findings

• At rest, the heart rate, mean right atrial pressure, mean pulmonary artery pressure, and mean pulmonary artery wedge pressure were notably lower than those observed during exercise.
• Exercise on the treadmill at 8 m/s caused noticeable increases in all the variables measured, including heart rate, right atrial pressure, pulmonary artery systolic, mean, diastolic, and pulse pressures, and pulmonary artery wedge pressure.
• As the workout intensity increased to 10 m/s and then to 13 m/s, all these variables except for the pulmonary artery diastolic pressure, also registered more significant increments.

Implications

• The increase in these variables during intense exercise suggests an increase in the pressure of the blood flow through the horses’ lungs as the workout intensifies.
• The workout intensity may challenge the cardiovascular system of the horses, particularly by increasing the intravascular pulmonary capillary pressure – a measurement that is estimated to be halfway between the mean pulmonary arterial and venous pressures.
• The transmural pressure (difference between intravascular and alveolar pressure) across pulmonary capillaries may have been even higher due to the considerable negative pleural pressure swings in galloping horses.
• These findings provide valuable insights that can help in understanding the cardiovascular responses and challenges that horses may face during intensive physical activity.