Intermittent claudication, exercise, and blood rheology.

Forty-two stable patients with claudication were assigned to two groups. Group I (n = 22) was submitted to regular, standardized treadmill exercise for 2 months. During this time the maximal and pain-free walking distances increased significantly (more than 100%). Group II (n = 20) patients did not exercise over the same period of time, and their walking distances remained essentially unchanged. No drugs or other forms of treatment were given in either group. The rheology of blood, as quantified by blood and plasma viscosity, hematocrit, blood filterability, and red cell aggregation, was initially abnormal in patients as compared with matched controls. Blood and plasma viscosity, blood cell filterability, and red cell aggregation normalized significantly in group I, but remained pathologic in group II. The hemorrheologic values of patients after 2 months of exercise did no longer differ significantly from those of healthy controls. The "fluidification" of blood induced by regular exercise was qualitatively and quantitatively similar to that obtainable by hemorrheologically active medications. The results confirm that physical training is clinically effective in patients suffering from claudication. They furthermore suggest that training may be looked on as a form of "hemorrheologic therapy" suitable for increasing the fluidity of blood in patients with ischemic diseases. Part of the benefits of regular exercise in stage II occlusive peripheral arterial disease may result from changes in hemorrheology; further studies are needed to define the mechanism.