High-speed treadmill running up to 105 m/min in male rats resulted in continued increases in hindlimb muscle blood flow without clear evidence of a plateau.
Does high-speed locomotion cause a plateau in muscle blood flow in rats?
In laboratory rats, muscle blood flow continues to increase without plateauing even at maximal treadmill speeds, suggesting cardiovascular potential during exercise is higher than normally assumed.
We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals' normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance.
Armstrong et al. (Tue,) reported a other. High-speed treadmill running was evaluated on Muscle blood flow. High-speed treadmill running up to 105 m/min in male rats resulted in continued increases in hindlimb muscle blood flow without clear evidence of a plateau.