Blood-gas, acid-base and haematological values in horses during an endurance ride.

This research paper studied the impact of a 100 km endurance ride on the arterial and venous oxygen tension, carbon dioxide tension, blood acidity, and several other factors in 36 horses, revealing significant changes in many parameters. Particularly, horses developed dehydration and a shift in blood pH towards the alkaline side.

Endurance Ride Impact on Horses

• The study sought to investigate the effects of a long-distance ride on different blood parameters of horses.
• The research involved 36 horses participating in a 100 km endurance ride and many blood values were monitored, including levels of oxygen and carbon dioxide in the blood, blood pH, bicarbonate, haemoglobin, packed cell volume and total plasma protein.

Significant Changes Observed

• Significant changes were recorded in many parameters when comparing initial values, mid-ride values, and end of ride values.
• The most noticeable changes were the development of dehydration and metabolic alkalosis, which is a condition that occurs when your blood becomes overly alkaline.
• It was also noted that during the mid-ride, horses with higher heart rates developed a higher degree of metabolic alkalosis compared to horses with lower heart rates.

Winning Horses Syndrome

• The first four horses which completed the ride with speeds between 322-330 m/min, and were presumably pushing their bodies more, demonstrated metabolic acidosis, which is a build up of acid in the body due to the use of muscle for energy.
• This finding suggests that in horses strained by endurance races, a shift can occur from an alkaline blood state to an acidic one. A state that is generally indicative of a body under significant physical stress.