Training and exercise change respiratory properties of blood in race horses.

The research article investigates how training and exercise impact the respiratory properties of blood in standard-bred race horses, showing significant increases in resting and active oxygen capacity, and a correlation between oxygen affinity and red cell concentration.

Increased Oxygen Capacity

• The study shows that training can significantly enhance the levels of circulating oxygen capacity, both at rest and during physical activity. For resting horses, oxygen capacity increased from 18.4 to 21.0 volume percent through training. During exercise, the difference proved even more remarkable, with oxygen capacity improving from 24.9 to 30.3 volume percent.

Change In Red Cell Concentration

• The research found a correlation between an increase in oxygen affinity (in vitro) and a decrease in the concentration of red cells containing 2,3-diphosphoglycerate (DPG), a crucial compound in releasing oxygen from red blood cells to the body tissues. This decrease was from about 6.35 millimolar per liter of erythrocytes, the red blood cells.

Impact on Trained Horses

• Trained horses show a further lowering of red cell DPG concentration immediately after maximal exercise, suggesting that the body adapts to the changes in oxygen aptitude through a decrease in DPG concentration.

Significance and Relationship to Other Physiological Changes

• The study discusses the physiological implications of increased oxygen capacity and oxygen affinity as a result of the decreased DPG concentration. It also proposes a hypothesis to elucidate the possible relationship among changes in spleenic size, total red cell volume, and red cell DPG concentration in response to exercise.

The exact dynamics and consequences of these changes are not detailed in the abstract but are likely addressed in the full paper. Through these finds, the study contributes to our understanding of how training affects the metabolic and physiological responses of race horses’ bodies.