Serum electrolyte and total protein alterations in Pantaneiro horse during long distance exercise

Blood samples were taken from eight Pantaneiro horses during a 76Km endurance ride. The horses were divided into two groups: 1- four horses kept on native pasture, without working and with no supplementation during one month before the ride, 2- four horses kept on native pasture with supplementation and submitted to work during one month before the ride. Serum concentration of total protein, albumin, sodium, potassium, chloride, calcium and phosphorus were measured. Samples were taken before the ride (preride), during the mid point (midride), at the end of the ride (postride) and after a 30-minute recovery period (rest). Sweat samples were collected from five horses at the end of the ride to measure sodium, potassium, and chloride. In the groups, there was a significant decrease in calcium and potassium, and an increase in sodium and phosphorus during the ride. Heart rate values after 30 minutes of rest indicated a good recovery response

Regulatory mechanisms of blood lactate production during exercise in man

During cycloergometric exercise at progressively increasing loads, blood lactate concentration increased about 12-fold. Pyruvate concentration decreased initially(for loads of 50-75 W), increased with loads of 75 to 125 W and then decreased again until the end of exercise. the malate concentration increased abruptly between 50 and 75 W, followed by a slow decline; citrate increased about nine-fold as the exercise load was increased to 125 W and then fell sharply. Thus, the production of lactate during low-intensity exercise seems to occur by the "mass-action effect" caused by enhanced glycolysis, whereas with moderate loads the glycolysis rate is very much reduced and most of the lactate production seems to involve the action of the malate-aspartate shuttle. For high-intensity exercise, both mechanisms appear to participate in lactate production