A description is given of a technique that provides a relatively simple means by which O2 consumption and hemodynamic variables can be measured in exercising dogs.
We used a multistage submaximal treadmill test to study the responses of 10 foxhounds to dynamic exercise.
They were also studied during maximal treadmill exercise.
O2 consumption increased from 16.3 /- 1.7 ml O2 X min-1 X kg-1 at rest to 92.9 /- 9.7 ml O2 X min-1 X kg-1 at a work load of 6.4 km/h, 20% grade and to 111.9 /- 9.6 ml O2 X min-1 X kg-1 during maximal exercise.
Cardiac output (CO) increased from 6.11 /- 0.45 l/min at rest to 16.91 /- 1.46 and 17.66 /- 0.60 l/min at 6.4 km/h, 20% grade and maximal exercise, respectively.
Arteriovenous O2 difference increased from 5.8 /- 0.3 vol% at rest to 12.0 /- 0.4 and 13.2 /- 0.7 vol% at 6.4 km/h, 20% grade and maximal exercise, respectively.
Heart rate (HR) increased from 116 /- 7 beats/min at rest to 250 /- 8 beats/min at 6.4 km/h, 20% grade and to 278 /- 6 beats/min during maximal exercise.
O2 uptake, CO, and arteriovenous O2 difference increased with the onset of exercise, appeared to level at lower work intensities (6.4 km/h, 4 and 8% grade), and increased significantly at each of the higher work intensities (6.4 km/h, 12, 16, and 20% grade).
Additionally, we observed linear relationships between O2 consumption and HR (HR = 1.35 X VO2 120.5; r = 0.87; P less than 0.001) and between O2 consumption and CO (CO = 5.91 X VO2 216.6; r = 0.96; P less than 0.001).
Further, the linear relationship between O2 consumption and CO demonstrated in the present study is similar to that observed in humans.
G. A. Ordway, D. L. Floyd, J. C. Longhurst, J. H. Mitchell