The effects of high intensity exercise on the plasma concentration of lactate, potassium and other electrolytes.

This research examines how short-term high-intensity exercise, such as galloping on a treadmill, affects the concentration of lactate, potassium, sodium, and chloride in the plasma of horses.

Objective and method of the study

• The experiment was designed to observe how short-term high-intensity exercise influences plasma lactate, potassium, sodium, and chloride. These effects were studied in five Thoroughbred horses who were made to gallop on a treadmill at a 5-degree incline.
• The horses galloped at various speeds of 8, 10, or 12 metres per second for 2 minutes. One horse also galloped at a speed of 14 metres per second for 1.5 minutes. This was done after a standard warm-up period.
• To monitor the concentrations of the selected items in the horses’ blood during exercise and recovery, sequential arterial and/or venous blood samples were collected.
• Furthermore, the effects of various recovery modes such as standing, walking, or trotting on electrolyte levels were also examined at the speed of 12 metres per second.

Findings

• During galloping, a progressive rise in plasma potassium concentration was observed. Peak values were typically recorded at the end of the exercise bout.
• At the highest workloads, some cases showed potassium levels above 10 mmol/litre.
• During the early recovery phase, plasma lactate concentrations were highest, with values reaching 32 mmol/litre.
• A significant correlation was found between peak potassium and lactate concentrations: venous r = 0.923 and arterial r = 0.989.
• Following exercise, plasma potassium concentration quickly returned to baseline. However, lactate concentration remained elevated at the 12-minute recovery mark. The intensity of the exercise bout and the mode of recovery impacted this condition.
• During exercise, there was a small increase in plasma sodium concentration and no significant change in chloride levels. However, when adjusted for the decrease in plasma volume (as determined from total plasma protein concentration), circulating amounts of both electrolytes decreased.

Conclusion

The study indicates a strong connection between rigorous exercise and certain physiological changes in Thoroughbred horses. It was observed that high-intensity exercise could cause an increase in potassium and lactate levels during the exercise and early recovery phase, which then reverts to normal or baseline levels, especially for potassium. The more intense the exercise or different recovery modes, however, might still leave an elevated level of lactate during the recovery phase.