Objectives: Our purpose was to examine the effect of cardiac rehabilitation and exercise training on blood rheology in patients with coronary heart disease (CHD). Although increased blood and plasma viscosity have been associated with an increased risk of CHD, the effects of cardiac rehabilitation and exercise training on blood rheology in patients with CHD are uncertain.
Methods: We assessed whole blood effective viscosity (mu), hematocrit standardized blood viscosity (mu45)), red blood cell transport efficiency (tau(rbc)), and plasma viscosity (PV) in 23 nonsmoking patients with CHD before and after a phase II cardiac rehabilitation and exercise training program. In addition, we compared the group data with the data of a healthy reference group of 10 subjects.
Results: Patients with CHD had significantly elevated mu (3.35 +/- 0.35 cp vs 3.06 +/- 0.19 cp, P <.05) and mu45 (3.51 +/- 0.29 cp vs 3.12 +/- 0.06 cp, P <.001) and reduced tau(rbc) (12.7% +/- 1.0% x cp(-1) vs 14.2% +/- 0.7% x cp(-1), P <.001) compared with healthy subjects. After rehabilitation, patients with CHD had reductions in PV (1.85 +/- 0.18 cp vs 1.77 +/- 0.11 cp, P <.01) and mu45 (3.58 +/- 0.22 cp vs 3.39 +/- 0.22 cp, P <.0001) and an increase in tau(rbc) (12.4% +/- 0.8% x cp(-1) vs 13.2% +/- 0.9% x cp(-1), P <.0001).
Conclusions: Cardiac rehabilitation improves blood rheology in patients with CHD by reducing mu45 and PV and elevating tau(rbc). These improvements may contribute to the increased functional capacity and reduced morbidity and mortality that is associated with participation in cardiac rehabilitation and exercise programs.