The effects of overtraining on blood volumes in standardbred racehorses.

The research investigates the impact of overtraining on the blood volumes of Standardbred racehorses, concluding that red cell hypervolaemia does not contribute to the decrease in exercise capacity associated with overtraining.

Study Overview

• This prospective study was conducted with 12 Standardbred horses over a period of 32 weeks.
• During this period, the horses’ plasma, blood, and red cell volumes were measured at the 8th and 32nd week.
• The horses were divided randomly into the over training (OLT) and the control group after 16 weeks of training.
• The intensity and duration of the training were significantly increased for the OLT group from week 16 onwards until overtraining was diagnosed in week 32.

Results and Findings

• The research found that overtraining had no significant impact on the horses’ plasma, blood or red cell volumes between weeks eight and 32.
• These volumes were observed to significantly decrease with time.
• In the 32nd week, the Over Training group exhibited a lower maximal haematocrit after exercise compared to the measurement taken in the 8th week.

Conclusion

• The research concluded that red cell hypervolaemia, or an excessive volume of red blood cells, does not serve as a mechanism for the decrease in exercise capacity that results from overtraining.
• This challenges the previous belief that red cell hypervolaemia was a major factor contributing to the loss of racing performance in overtrained horses.