Effect of Exercise Testing on Lipid Peroxide Levels of Plasma and Erythrocyte Ghosts

抄録

This study was designed to detect whether the plasma level of lipid peroxide and of erythrocyte ghost (EG) would be affected by treadmill exercise testing carried out by the modified Bruce method in patients with hypertension or hypercholesterolemia. A total of 27 patients were studied for changes in their ECG. On exercise testing, 10 patients responded positively and 17 negatively. Before testing, plasma levels of lipid peroxide were 3.9±0.9nmol/ml (mean±SE) in the positive group and 1.6±0.4nmol/ml in the negative group, a significant difference (p<0.05). The lipid peroxide (LPO) level of the EG was 3.7±0.8nmol/mg protein in the positive group and 3.2±0.7nmol/mg protein in the negative group. Exercise testing tended to induce a rise in the lipid peroxide values in the EG of the positive group (11.3±5.0nmol/mg protein vs. 3.7±0.8nmol/mg protein, p<0.1). The fold-increase in the level of erythrocyte membrane lipid peroxide was significantly higher in the positive responders (2.3±0.7 vs. 0.8±0.1, p<0.05). There was no significant change in the plasma level of lipid peroxide in either group. Other clinical parameters including blood pressure, heart rate, obesity, smoking, medication, exercise intensity, and plasma lipid levels showed no differences between the positive and the negative responders. We conclude that the erythrocyte membranes of the positive responders to treadmill exercising are easily peroxidized by various stimuli, which may contribute in part to the high plasma lipid peroxide level before testing. A stimulus such as treadmill testing may accelerate the lipid peroxidation of the erythrocyte membranes significantly and independently.