Effects of Triphasic Exercise on Blood Rheology and Pathophysiology

The aim of this work is to study the relevance of physiology and pathophysiology in blood rheology as effects of triphasic exercise. Regular exercise which has been established as life prolonging has led to decrease in both peripheral vascular and coronary morbidity that has been associated with certain improvements in cardiovascular disease (VCD) risk factors. Haemorheology is affected by exercise, which has a possible connection between beneficial haemodynamics and metabolism. This is affected by exercise of any type. A possible link between the beneficial metabolic and haemodynamic effects of exercise could be blood rheology, which is markedly affected by exercise. It was proposed here a description of the haemorheological effects of exercise as a triphasic phenomenon. Short-term effects of exercise are an increase in blood viscosity resulting from both fluid shifts and alterations of erythrocyte rheological properties (rigidity and aggregability). Increased blood lactate, stress and acute phase play a role in this process. Middle-term effects of regular exercise are a reversal of these acute effects with an increase in blood fluidity, explained by plasma volume expansion (autohaemodilution) that lowers both plasma viscosity and haematocrit. Long term effects further improve blood fluidity in parallel with the classical training-induced hormonal and metabolic alterations. While body composition, blood lipid pattern, and fibrinogen improve (thus decreasing plasma viscosity), erythrocyte metabolic and rheologic properties are modified, with a reduction in aggregability and rigidity. On the whole, these improvements reflect on reversal of the so-called “insulin-resistance syndrome” induced by a sedentary life-style. Since impaired blood rheology has been demonstrated to be a risk for vascular diseases, the haemorheologic effects of exercise can be hypothesized to be a mechanism (or at least a marker) of risk reversal. The latter point requires further investigation. The physiological meaning of the triphasic pattern of exercise-fluidity may improve several steps of oxygen transfer to the muscle, as clearly demonstrated in hypoxic conditions. Increasing evidence emerges from the literature, that blood fluidity is a physiological determinant of fitness. Keywords: Triphasic exercise, blood rheology, aggregation, physiology. Journal of Medical Laboratory Sciences Vol. 14 (2) 2005: pp. 13-22