Low-volume high-intensity interval training vs continuous aerobic cycling in patients with chronic heart failure: a pragmatic randomised clinical trial of feasibility and effectiveness.
OBJECTIVE
The health benefits of high-intensity interval training in cardiac rehabilitation warrant further research. We compared the effectiveness of low-volume high-intensity interval training vs continuous aerobic exercise training in chronic heart failure.


METHODS
Unblinded, two arm parallel design with random assignment to exercise interventions in out-patient hospital rehabilitation gym.


METHODS
Patients with signs of chronic heart failure and ejection fraction < 45%, (mean age: 59.1 years (standard deviation (SD) 8.6); 3 women) completed 6 months of exercise using continuous aerobic exercise training (n = 9) or high-intensity interval training (n = 8). Cardiorespiratory fitness was determined during cycle ergometry using respiratory gas exchange analysis. Functional capacity was assessed via sit-to-stand and gait speed. Quality of life was assessed using the MOS Short-Form 36 and Minnesota living with heart failure questionnaires. Cardiac autonomic regulation was assessed using Heart Rate Variability.


RESULTS
Analysis of Covariance revealed significant time effects but no group × time interactions for exercise and functional capacity outcomes. Peak oxygen uptake (VO2peak) improved by a mean of 14.9% (SD 16.3%) from baseline and by 22% (SD 28.3) at ventilatory threshold in both groups. Sit-to-stand (11.9 (SD 11%)) and gait speed (16.0 (SD 19%)) improved similarly in both groups. No changes in quality of life or heart rate variability were noted. Training adaptations in high-intensity interval training were achieved despite a significantly reduced time commitment and total work volume compared to continuous aerobic exercise training.


CONCLUSIONS
Low-volume high-intensity interval training is a feasible and well tolerated training modality in cardiac rehabilitation settings, but is not more effective than continuous aerobic exercise training.
School of Health Sciences, Queen Margaret University, EH21 6UU Edinburgh, United Kingdom. pkoufaki@qmu.ac.uk.
Pelagia
P
Koufaki
Thomas H
TH
Mercer
Keith P
KP
George
James
J
Nolan
D002908:Chronic Disease; D015444:Exercise / Q000502:physiology / Q000523:psychology*; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods* / Q000523:psychology*; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000534:rehabilitation*; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D010045:Outpatients; D011788:Quality of Life; D016896:Treatment Outcome