Elemental composition of muscle at rest and potassium levels in muscle, plasma and sweat of horses exercising at 20 degrees C and 35 degrees C.

The research article explores the correlation between exercise intensity and variations in the elemental composition in muscle tissues, blood plasma, and sweat of horses at resting and exercising stages at two different temperatures.

Methodology

• In this experiment, four Standardbred geldings were used as subjects. They were exercised at two different temperatures: 20 and 35 degrees Celsius. The horses underwent two bouts of exercise with a two-hour rest period in between.
• Horses underwent a muscle biopsy from the gluteus medius muscle before the first exercise bout and after an intensive trot in the second exercise bout covering a distance of 2600 meters.
• Blood samples were collected before, during, and after the second bout of exercise. These were analyzed for plasma potassium concentration and total plasma protein concentration (TPP).
• Muscle fibers were scrutinized for their elemental composition, including levels of sodium, magnesium, phosphorus, sulfur, chloride, potassium, and calcium, using x-ray microanalysis.

Findings

• Baseline elemental composition in the horses’ muscle fibers was established. This showed the intracellular content of the various elements in normal conditions.
• An increase in intracellular potassium content was observed after exercise as compared to resting values.
• A strong correlation was found between exercise intensity, plasma potassium concentration, and shifts in plasma volume. This correlation was identified through alterations in TPP. This is likely to be a reflection of the rapid shift of potassium and fluid between muscle and plasma during exercise.
• Post-exercise, plasma potassium concentrations decreased below resting values.
• The increase in dehydration and potassium sweat loss after exercising at a higher temperature (35 degrees Celsius) didn’t result in a reduced muscular potassium content. However, a lower plasma potassium/total plasma protein ratio post-exercise was observed, indicating a lesser amount of circulating potassium within the body.

Implications

• The research implies that exercise intensity and temperature can gravely influence the balance and distribution of essential elements within the body of horses, specifically in muscle tissues, blood plasma, and sweat.
• The study can help in understanding how the rapid shift of potassium and fluid takes place between muscle cells and blood plasma during exercise, and how dehydration affects this process.
• Understanding the linkages between exercise, temperature, and elemental balance in horses could also prove useful for developing optimized training strategies and diet plans for horses, especially for race or work horses.