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Exercise intolerance, a key symptom of chronic heart failure, has been linked to peripheral derangements, and marked endothelial dysfunction (i. e. the inability of endothelium to medi­ate a proper vasodilatatory response to physiologic stimuli) has been postulated to be one of the main causes. We hypothesized that supervised aerobic leg training improves endothe­lial function in the upper limb vessels.

In our prospective study, 24 patients (3 women, 21 men, aged 50−80 years) with chron­ic heart failure were randomized to a control or a training group, which attended one-hour training sessions 3 times a week for 8 weeks. Before and after the training period, clinical and biochemical parameters, exercise capacity as well as endothelial dysfunction were deter­mined. Endothelial dysfunction was assessed by high-resolution ultrasound measurements of brachial artery diameter and peak flow velocity at rest, after reactive hyperemia (caus­ing flow-mediated endothelium-dependent dilation), and after gylceriltrinitrate administration (causing endothelium-independent vasodilatation).

Endothelium-dependent vasodilatation improved in training patients from 4.2 ±2.1% (mean ± standard deviation) to 7.7 ±2.3% (p<0.05), while the control group patient showed no significant change. Exercise capacity increased in the training group from 5.21 ± 1.13 to 6.88 ±1.29 metabolic equivalents, and double product (systolic blood pressure x heart rate at maximal exercise capacity) improved from a median value of 16.73 (1^st−3^rd quartile range 15.9−18.53) to 18.25 (range 16.57−21.67) mm Hgx min^-1 x 10³ (p<0.05), while both parameters remained unchanged in the control group. Body mass index, systolic and diastolic blood pres­sure, heart rate, and blood lipid levels did not change significantly in either group. Endothelium-dependent vasodilatation was negatively correlated with heart rate (r = −0.22, p < 0.05), and the change in endothelium-dependent vasodilatation in the control group was correlated with changes in exercise capacity (r = 0.34, p<0.05).

Our findings suggest that eight-week aerobic leg training improves brachial artery flow-mediated vasodilatation. Since leg training improved brachial artery endothelial func­tion, it can be assumed that systemic effects of training on skeletal muscle vasculatrure are involved.