A randomised, controlled study of the effects of aerobic exercise and dietary fish on coagulation and fibrinolytic factors in type 2 diabetics

SummaryType 2 diabetes is associated with disturbances in coagulation and fibrinolysis. Prospective studies show that increased tissue plasminogen activator (tPA) antigen increases the risk of cardiovascular mortality. The present study examined the hypothesis that combining a regime of moderate aerobic exercise with one daily fish meal as part of a low-fat diet (30% total energy) would improve coagulation and fibrinolytic factors in dyslipidaemic type 2 diabetic patients. In a randomised, controlled, 8-week trial, 55 sedentary type 2 diabetic subjects with serum triglycerides >1.8 mmol/l and/or HDL-C <1.0 mmol/l were randomly assigned to a low-fat diet (30% daily energy intake) with or without one fish meal daily (3.6 g ω3 fatty acids/day) and further randomized to a moderate (55-65% VO2max) or light (heart rate <100 bpm) exercise program. Plasma levels of fibrinogen, coagulation factor VIIc, tPA and plasminogen activator inhibitor (PAI-1) antigen were measured before and after intervention. In the 49 subjects who completed the study, the fish diet alone, moderate exercise alone and the combination of fish and moderate exercise all led to significant reductions in tPA antigen concentrations (-2.1 ng/ml, p = 0.02, -1.9 ng/ml, p = 0.03, -2.0 ng/ml, p = 0.01, respectively) compared to controls. In multivariate regression, changes in fasting blood glucose (positively) and erythrocyte ω3 fatty acid composition (inversely) were independent predictors of the change in tPA antigen. The fish diet alone contributed to a significant rise in coagulation factor VIIc compared to controls (4.9%, p = 0.02), which was prevented by moderate exercise. No significant effects on PAI-1 antigen and fibrinogen were seen. In view of recent epidemiological findings, the reduction in tPA antigen with both fish and moderate exercise in these dyslipidaemic type 2 diabetic patients could reflect a reduced thrombotic potential and decreased cardiovascular risk. Furthermore, a small, albeit significant, increase in coagulation factor VIIc associated with fish can be prevented by a concomitant programme of moderate exercise.