The effect of agility exercise on eicosanoid excretion, oxidant status, and plasma lactate in dogs

Hematocrit, red blood cells (RBC), albumin, and hemoglobin increased following exercise, with greatest increases correlating to increased skill group (novice, intermediate, masters); at 4-hours post-exercise, hematocrit, RBC, and hemoglobin were decreased. Phosphorus increased following exercise with the greatest increase in novice and intermediates. Plasma lactate increased 3.6-fold in masters, 3.2-fold in intermediates, and 1.2-fold in novice dogs. Urine thromboxane B2 (TXB2) more than tripled 4-hours post-exercise while 6-keto prostaglandin F1α (PGF1α, prostacyclin metabolite), prostaglandin E2 metabolites (13,14-dihydro-15-keto-prostaglandin A2 and 13,14-dihydro-15-keto-prostaglandin E2), and 13,14-dihydro-15-keto prostaglandin F2α were unaffected as determined by a competitive enzyme immunoassay and standardized by division with urine creatinine. Urine 15F2t-isoprostane increased insignificantly.Alterations in the plasma post-exercise were likely due to hemoconcentration from insensible water loss, splenic contraction and sympathetic stimulation while 4-hours later autohemodilution reduced RBC parameters. Elevations in plasma lactate and urinary TXB2 correlated with advanced skill level/speed of the dogs.The United States Dog Agility Association (USDAA) alone, registers over 25,000 competitors and organizes over 400 days of agility competitions each year in the United States, Puerto Rico, Canada, Mexico, Bermuda, and Japan [1]. The percentage of dogs injured during agility exercise is estimated at 33% [2]. With such a high rate of injury, determining the effects of this type of exercise on the physiologic responses of dogs including the degree of oxidant stress and eicosanoid production induced by this exercise, is important to understanding why injury rates are so high.Canine agility exercise has been shown to induce significant increases in blood lactate and hence an anaerobic metabolic state [3,4]. In addition, plasma chloride, hematocrit, and triglycerides