Heart rate variability, exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate cystic fibrosis.
Pitiguara de Freitas Coelho, Roberta Ribeiro Batista Barbosa, Rodrigo Dos Santos Lugao and 4 others
PMID 35782696WHAT IT FOUND
Children and adolescents with mild-to-moderate cystic fibrosis who had abnormal heart rate variability showed worse lung function and lower exercise capacity.
Resting heart rate variability may serve as a non-invasive marker to identify patients with greater physical impairment.
Key findings
01Participants with abnormal resting heart rate variability had significantly worse lung function and lower exercise capacity compared to those with normal variability.
02Heart rate variability indices during exercise correlated positively with lung function and daily moderate-to-vigorous physical activity levels.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The cross-sectional design means the study cannot prove that abnormal heart rate variability causes worse outcomes, only that they are associated. The sample size was small (30 participants), limiting the generalizability of the findings. The study did not use cardiopulmonary exercise testing (CPET), the gold standard for assessing exercise capacity, relying instead on the Modified Shuttle Test. The participants were aged 6-18, but the discussion notes the sample characteristics (aged 8-15) may introduce variability related to puberty that was not controlled for.
Declared interests
The authors declared no conflicts of interest. The work was supported by Brazilian government research agencies (CAPES and CNPq).
The easy way to misread this
Do not assume heart rate variability abnormalities are the cause of the reduced exercise capacity or lung function. This is a cross-sectional study showing an association, so it cannot determine which came first or if a third factor influences both.