Impact of Exercise Training at Different Intensity Levels on Cardiac Function and Exercise Capacity in Patients with Chronic Heart Failure: A Prospective Cohort Study.
Zhenying Zhang, Lizhong Wang, Jianing Xi and 2 others
PMID 36264054WHAT IT FOUND
Both moderate and higher-intensity cycling improved heart failure symptoms and exercise capacity.
The higher-intensity group showed greater gains in peak oxygen uptake and workload than the moderate group. All patients also received medication, education and lifestyle advice, so the exercise component's contribution cannot be isolated.
Key findings
01Exercise at Δ50% power above anaerobic threshold produced significantly higher peak VO2, peak O2 pulse and peak workload than exercise at 80% anaerobic threshold after 12 weeks.
02Both exercise groups improved left ventricular ejection fraction, 6-minute walk distance and health-related quality of life significantly compared with the non-exercise group, with no significant difference between the two exercise intensities.
03No serious cardiac events occurred during the 12-week programme, and both exercise groups completed training safely.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Single-centre study with only 45 participants (15 per group), limiting generalisability. Only 13% of participants were female, so findings may not apply equally to women. Patients were excluded if they could not exercise at the required intensity or had been unstable for less than a month, creating selection bias toward more stable, capable patients. All patients received medication, education and lifestyle advice alongside exercise, so the independent effect of exercise intensity cannot be separated from these concurrent interventions. Group assignment was based on clinical discussion rather than randomisation, so baseline differences could influence outcomes despite reported comparability.
Declared interests
No funding source or conflicts of interest are declared in the supplied text.
The easy way to misread this
Do not conclude that higher-intensity exercise is superior for all heart failure patients. The groups were not randomised, the sample was small and highly selected (only stable patients who could exercise), and all participants received concurrent medication, education and lifestyle interventions. The difference in peak oxygen uptake between intensities cannot be separated from these co-interventions or from potential baseline imbalances.