Dissociated effects of physical activity and weight loss on fibrinogen concentrations and markers of red blood cell aggregation. Relevance for life style modification in atherothrombosis

It has been shown that weight loss and physical activity contribute to a better biorheological profile. Yet, the concentrations of fibrinogen are not always reduced following life style modification. We evaluated the inter-relations between fibrinogen's pro red cell aggregation potential and reduced inflammation and improved lipid profile as anti-aggregating forces in a group of 20 apparently healthy obese volunteers following 4 and 8 months of intensive life modification program which included diet and strenuous physical activity. A significant (p=0.005) weight loss (from a mean±SD of 121.4±20.9 to 98.0±21.3 kg) and decrease in body mass index (from 40.8±4.3 to 32.9±5.3 kg/m², p=0.005) was noted in fourteen individuals who completed the 8-month program. The concentrations of clottable fibrinogen rose from 318±96 to 387±72 mg/dl (p=0.012) while there was a significant reduction in the erythrocyte sedimentation rate (ESR) (from 19.0±12.6 to 10.8±7.5 mm/h, p=0.018), triglycerides (from 143±80 to 80±44 mg/dl, p=0.005), LDL cholesterol (from 128±34 to 103±17 mg/dl, p=0.005) and total cholesterol (from 211±40 to 171±17 mg/dl, p=0.007), as well as decrease in insulin concentration (from 36.1±21.3 to 20.6±8.0 μu/ml, p=0.01) and the insulin resistance index (HOMA-R, from 9.1±6.4 to 4.9±2.1 glu*ins/405, p=0.008). Despite a significant increment in the concentrations of clottable fibrinogen, a significant reduction was noted in the degree of red cell aggregation as measured by using a slide test and direct visualization of the aggregates. Our conclusion is that the pro-aggregating properties of fibrinogen following intense physical activity are probable counterbalanced by the anti-aggregatory properties of an improved lipid profile and an attenuated acute phase response.