Key result
A 2-month high-intensity training program in heart failure patients increased the oxygen uptake efficiency slope by 12% (P=0.003) and improved exercise capacity, but did not change the VE/VCO2 slope.
Why the study?
Does a 2-month high-intensity training program improve indices of ventilatory efficiency and exercise capacity in patients with chronic heart failure?
RCT (n=50)
Does a 2-month high-intensity training program improve indices of ventilatory efficiency and exercise capacity in patients with chronic heart failure?
Absolute Event Rate: 12% vs 4%
p-value: p=0.003
A 2-month high-intensity training program significantly improves exercise capacity and the oxygen uptake efficiency slope (OUES) in patients with chronic heart failure, though it does not alter the VE/VCO2 slope.
High-intensity training boosts OUES and exercise capacity in HF; extends RCT evidence on ventilatory efficiency without altering VE/VCO2.
BACKGROUND: Measures of ventilatory inefficiency, such as the slope of the relation between ventilation and carbon dioxide production ((Equation is included in full-text article.)slope) and the oxygen uptake efficiency slope (OUES) have recently been shown to be strong prognostic markers in patients with heart failure. Little is known regarding the effects of exercise training on these indices. METHODS: Fifty heart failure patients (mean age = 55 ± 6 years, ejection fraction = 33 ± 6%) referred to a residential cardiac rehabilitation program were randomized to a 2-month high-intensity training program (n = 24) or to a control group (n = 26). Before and after the study period, maximal cardiopulmonary exercise testing was performed, and markers of ventilatory inefficiency were determined. RESULTS: Training increased peak oxygen uptake ((Equation is included in full-text article.); 23%), exercise time (29%), and peak workload (28%), whereas no changes were observed in controls (all P < .05 between groups). No differences were observed in the (Equation is included in full-text article.)slope in either group. However, the ventilatory equivalent for oxygen ((Equation is included in full-text article.)ratio) was reduced at matched work rates throughout exercise (P < .01). The OUES increased by 12% in the exercise groups (P = .003) and 4% in controls. At baseline, trained patients had an OUES that was 69% of the age-predicted value and this improved to 78% after training (P = .004). The change in OUES was significantly related to the change in peak (Equation is included in full-text article.)with training (r = 0.63, P = .001). CONCLUSION: High-intensity training resulted in marked improvements in exercise capacity in patients with heart failure. Training improved the OUES and reduced the (Equation is included in full-text article.)ratio, but the (Equation is included in full-text article.)slope was unchanged. Among measures of ventilatory inefficiency, the OUES may be more sensitive to training than the (Equation is included in full-text article.)slope.
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Myers et al. (2012) conducted an RCT in Chronic Heart Failure (n=50). High-intensity training program vs. Control group was evaluated on Oxygen uptake efficiency slope (OUES) (p=0.003). A 2-month high-intensity training program in heart failure patients increased the oxygen uptake efficiency slope by 12% (P=0.003) and improved exercise capacity, but did not change the VE/VCO2 slope.
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