Journal of Applied Physiology, Vol 45, Issue 5 728-732, Copyright © 1978 by American Physiological Society
Exercise performance and hemodynamics during dietary potassium depletion in dogs
H. S. Lowensohn, R. E. Patterson and R. A. Olsson
Dietary potassium depletion plus high sodium intake has been reported to
elevate resting heart rate and cardiac output and to cause heart failure
during exercise. We implanted aortic root electromagnetic flowmeters and
aortic and pulmonary artery catheters in five splenectomized dogs
condition-trained to run at 9 km/h on an 11% grade for 20 min.
Postoperatively, the dogs ate a potassium-enriched diet until completion of
control studies; then potassium was withdrawn. During 4 wk of depletion,
skeletal muscle potassium fell from 380 +/- 22 to 311 +/- 8 meq/kg, and
muscle sodium rose from 142 +/- 14 to 207 +/- 27 meq/kg (mean +/- SE).
Cardiac output, aortic blood pressure, heart rate, acceleration of aortic
blood flow at rest or during exercise, and the oxygen cost of exercise
remained at control levels. Serum creatine phosphokinase at rest, an
indicator of rhabdomyolysis, was never elevated. A 24% dietary depletion of
muscle potassium in the dog did not change resting and exercise
hemodynamics and exercise performance from control.
