Effects of prerace exercise, frusemide, sex and ambient temperature on blood sodium, bicarbonate and pH values in standardbred horses.

The study investigates how pre-race exercise, the use of a diuretic drug-frusemide, gender/age, and ambient temperature affect the concentration of sodium, bicarbonate and the pH level in the blood of standardbred horses. The researchers propose adjustments to standard limits for these factors in pre-race blood tests, which could enhance the accuracy of detecting prohibited alkalogenic substances and minimize erroneous test results.

Significant Influences on Blood Chemistry

• The study statistically establishes certain factors significantly influence the concentration of sodium, bicarbonate and pH value in standardbred horses’ blood. These include pre-race exercise, administration of the drug frusemide, ambient temperature, a combination of temperature and exercise, along with the interaction of sex and age.
• Temperature and the administration of frusemide significantly impacted sodium concentration where they often affected how much sodium was present in the horses’ blood post-race.
• The influence of exercise, in conjunction with temperature, appeared to have a substantial effect on the horses’ blood pH and bicarbonate ion concentration. As the study discovered, this had an interaction effect, meaning the combined effects were not just additive but could potentially amplify one another.
• Interestingly, the sex/age interaction of the horses seemed to have a bearing on both pH and bicarbonate ion concentration. The meaning is that the impact of age and gender together may have a greater effect on these blood components than each factor alone.

Implications for Prerace Testing

• Currently, the prerace testing procedures utilized involve predetermined ‘normal’ range limits for sodium, bicarbonate and pH. These limits are used to determine whether a horse may have been given illicit alkalogenic substances (substances that increase the pH level of bodily fluids).
• If these substances were present, they could potentially mask the presence of other prohibited performance-enhancing substances and thereby allow illicit practices to go undetected.
• The researchers suggest adjusting the standard limits for these blood components considering pre-race exercise, frusemide administration, and the ambient temperature. Such adjustments will refine the prerace testing procedures and increase their precision.
• More precise testing eliminates an incorrect identification of prohibited substance use, termed as ‘false positives’ and ‘false negatives’. This means fewer horses being incorrectly flagged for prohibited substance use, and fewer horses wrongly clear in their test results. This makes testing more accurate and fair, benefiting both the horses and their handlers.