Exercise-induced transient hyperlipidemia in the racehorse.

This research article investigates the effects of varying intensity exercise on plasma lipids in Standardbred and Finnishbred Trotter racehorses, highlighting the association between intensity of exercise and change in plasma lipids.

Research Objectives and Study Design

• The main aim of this study was to understand how varying intensities of exercise influences plasma lipid levels in standardbred and Finnishbred trotter horses.
• As a secondary objective, the study sought to identify if there were significant differences in the responses between the two breeds, which might carry implications for recovery patterns after submaximal exercises.
• The research measured plasma concentrations of lipids like glycerol and triglycerides before, during, and after exercises of different intensities.

Findings

• The study found that the rate of lipolysis, indicated by rising plasma concentrations of glycerol, increased in parallel with the intensity of trotting exercise in Standardbred horses.
• This correlation wasn’t as clear in Finnishbred trotters, suggesting potential breed differences in lipid metabolism during exercise.
• The researchers noted a significant increase in plasma triglyceride concentration with exercise, and this increase correlated both with the intensity of the exercise and the rate of lipolysis.
• Notably, there was a parallel increase in the pre-beta fraction of lipoproteins, suggesting a consequent rise in hepatic synthesis of triglycerides during exercise.

Conclusions and Implications

• Horses, similar to humans, experience exercise-induced transient hyperlipidemia, where the level of lipids in the bloodstream increases during and shortly after exercise then returns to normal.
• It was estimated that about one-third of the nonesterified fatty acids released in lipolysis during high-intensity exercise is oxidized while the rest is used for resynthesis of triglycerides.
• There were clear inter-breed differences, as indicated by the differing concentrations of triglycerides and glycerol following high-intensity exercise in Standardbred versus Finnishbred trotters.
• This might be a significant factor in predicting recovery following submaximal exercises, something of practical importance in the horse-racing industry.