Study objectives: To test the effects of exercise training on sleep and neurovascular control in patients with systolic heart failure with and without sleep disordered breathing.
Design: Prospective interventional study.
Setting: Cardiac rehabilitation and exercise physiology unit and sleep laboratory.
Patients: Twenty-five patients with heart failure, aged 42 to 70 years, and New York Heart Association Functional Class I-III were divided into 1 of 3 groups: obstructive sleep apnea (n=8), central sleep apnea (n=9) and no sleep apnea (n=7). INTERVENTIONS Four months of no-training (control) followed by 4 months of an exercise training program (three 60-minute, supervised, exercise sessions per week).
Measures and results: Sleep (polysomnography), microneurography, forearm blood flow (plethysmography), peak VO2, and quality of life were evaluated at baseline and at the end of the control and trained periods. No significant changes occurred in the control period. Exercise training reduced muscle sympathetic nerve activity (P < 0.001) and increased forearm blood flow (P < 0.01), peak VO2( P < 0.01), and quality of life (P < 0.01) in all groups, independent of the presence of sleep apnea. Exercise training improved the apnea-hypopnea index, minimum 0O saturation, and amount stage 3-4 sleep (P < 0.05) in patients with obstructive sleep apnea but had no significant effects in patients with central sleep apnea.
Conclusions: The beneficial effects of exercise training on neurovascular function, functional capacity, and quality of life in patients with systolic dysfunction and heart failure occurs independently of sleep disordered breathing. Exercise training lessens the severity of obstructive sleep apnea but does not affect central sleep apnea in patients with heart failure and sleep disordered breathing.