Lactate, pyruvate and blood gases in the carotid artery, jugular vein and pulmonary artery during submaximal exercise

Abstract

Summary Research in exercise physiology in horses often involves the use of venous blood from the jugular vein to evaluate metabolic events. The advantage of sampling from the jugular vein is the ease and safety of collection. However, the use of jugular blood to evaluate exercise responses assumes that the venous blood returning from the head is representative of central circulation. These data were collected to determine whether differences exist between venous, mixed venous (pulmonary artery), and arterial blood for several parameters commonly measured during exercise. Four Quarter Horse mares with catheters placed in the carotid artery (CA), pulmonary artery (PA), and jugular vein were exercised for 15 minutes at 4.5 m/sec on a treadmill set at an 11% grade. The parameters measured were lactate, pyruvate, PO 2 , PCO 2 , and pH. As would be expected, time*location interactions (p 2 , and PCO 2 . Blood pH and PO 2 were highest in the CA and lowest in the PA. During exercise, PCO 2 increased in the PA and decreased in the JV and CA. Interestingly, a time*location interaction occurred for pyruvate (P