Influence of training on plasma adrenaline and noradrenaline kinetics in untrained standardbreds.

The research studied the effects of training on the levels of adrenaline and noradrenaline — substances involved in exercise response — in untrained Standardbred horses and discovered that training routines significantly reduce these substances, particularly during the initial training period.

Objective of the Study

• The research sought to investigate the variations in plasma catecholamines (adrenaline and noradrenaline) during training in untrained Standardbred horses.
• This is relevant because catecholamines play a critical role in moderating the body’s response to physical exercise.

Methods Used in the Study

• Four untrained Standardbred horses were first adapted to treadmill work, and then subjected to a standardized exercise test (SET).
• These tests were carried out before the start of training (SET1), and then one month (SET2), and two months (SET3) after the commencement of moderate training on a treadmill.
• The SET procedure included a warm-up and a two-minute single step at a heart rate of 200 beats per minute.
• An automatic blood collection system collected blood samples every 15 seconds during the SET procedure, and the results were analyzed using High-Performance Liquid Chromatography (HPLC).
• The progress of the training was monitored by measuring the anaerobic threshold velocity and the velocity during the SET procedure. Statistical analysis was carried out using Wilcoxon’s test.

Results of the Study

• It was found that the levels of adrenaline and noradrenaline in the horses’ blood decreased significantly after the training, particularly between the pre-training period (SET1) and the readings taken one month after (SET2) and two months after (SET3) the start of training.
• There were no significant differences in the adrenaline and noradrenaline levels between SET2 and SET3.

Conclusions of the Study

• The study concluded that training influenced the level of plasma catecholamines, and this influence was stronger during the initial training period for untrained Standardbreds.
• The study suggests that incorporating an analysis of training-induced modifications in plasma catecholamine concentration could be beneficial in understanding adaptations in thermoregulation during training, since thermoregulation is under catecholaminergic control.