Effect of physical exercise on lipoprotein(a) and low-density lipoprotein modifications in type 1 and type 2 diabetic patients

To evaluate the effect of physical exercise on blood pressure, the lipid pr ofile, lipoprotein(a) (Lp(a)), and low-density lipoprotein (LDL) modificati ons in untrained diabetics, 27 diabetic patients (14 type 1 and 13 type 2) under acceptable and stable glycemic control were studied before and after a supervised 8-month physical exercise program. Anthropometric parameters, insulin requirements, blood pressure, the lipid profile, Lp(a), LDL composi tion, size, and susceptibility to oxidation, and the proportion of electron egative LDL (LDL(-)) were measured. After 3 months of physical exercise, ph ysical fitness improved (maximal O-2 consumption [Vo(2max)], 29.6 +/- 6.8 v 33.0 +/- 8.4 ml/kg/min, P < .01). The body mass index (BMI) did not change , but the waist circumference (83.2 +/- 11.8 to 81.4 +/- 11.2 cm, P < .05) decreased significantly. An increase in the subscapular to triceps skinfold ratio (0.91 +/- 0.37 v 1.12 +/- 0.47 cm, P < .01) and midarm muscle circum ference ([MMC], 23.1 +/- 3.4 v 24.4 +/- 3.7 cm, P < .001) were observed aft er exercise. Insulin requirements (0.40 +/- 0.18 v 0.31 +/- 0.19 U/kg/d, P < .05) and diastolic blood pressure (80.2 +/- 10 v 73.8 +/- 5 mm Hg, P < .0 1) decreased in type 2 diabetic patients. High-density lipoprotein choleste rol (HDL-C) increased in type 1 patients (1.48 +/- 0.45 v1.66 +/- 0.6 mmol/ L, P < .05), while LDL cholesterol (LDL-C) decreased in type 2 patients (3. 6 +/- 1.0 v 3.4 +/- 0.9 mmol/L, P < .01). Although Lp(a) levels did not var y in the whole group, a significant decrease was noted in patients with bas eline Lp(a) above 300 mg/L (mean decrease, -13%). A relationship between ba seline Lp(a) and the change in Lp(a) (r = -.718, P < .0001) was also observ ed. After the exercise program, 3 of 4 patients with LDL phenotype B change d to LDL phenotype A, and the proportion of LDL(-) tended to decrease (16.5 % +/- 7.4% v 14.0% +/- 5.1%, P = .06). No changes were observed for LDL com position or susceptibility to oxidation. In addition to its known beneficia l effects on the classic cardiovascular risk factors, regular physical exer cise may reduce the risk of cardiovascular disease in diabetic patients by reducing Lp(a) levels in those with elevated Lp(a) and producing favorable qualitative LDL modifications. Copyright (C) 2000 by W.B. Saunders Company.