Effects of propranolol and verapamil on plasma ionized calcium and parathyroid hormone in short-term intense isokinetic leg exercise.

Physical exercise, beta-adrenergic stimulation and calcium channel blockade can affect calcium homeostasis. The present study investigated, in eight healthy males, the effects of orally administered propranolol or verapamil during a 2-min maximal, isokinetic, leg exercise. Immediately after exercise the plasma ionized calcium concentrations were increased, in control and drug tests, by 5-6%, and within 5 min of recovery they were almost returned to baseline. Serum parathyroid hormone (PTH) concentrations were unchanged at termination of exercise, but they increased during the first 5 min of recovery, coincident with the decline in calcium concentrations, which, however, were still elevated. Neither verapamil nor propranolol selectively changed basal or exercise plasma ionized calcium or serum PTH concentrations. Muscle strength, blood pH, lactate concentrations and plasma volume changes were not affected by any drug. Verapamil did not have any specific effect on the concentrations of plasma magnesium, phosphate, potassium or sodium while propranolol increased the concentrations of plasma potassium and decreased those of phosphate during exercise as well as recovery.