Plasticity of the heart in response to changes in physical activity.
Level 5 - mechanism / opinion, no new human data
Narrative review of human physiology without systematic search methodology
PubMed 39162309 · doi:10.1113/JP284158
What was done
Narrative review summarizing literature on human cardiac structural and functional plasticity across varying states of physical activity, including bed rest, spaceflight, sedentary aging, and endurance exercise training.
What was found
No numerical data are reported in the abstract. Severe deconditioning from bed rest or spaceflight results in cardiac atrophy and ventriculo-vascular stiffening. Endurance exercise training induces eccentric hypertrophy and enhances ventricular compliance, counteracting inactivity-induced changes. Sedentary aging leads to concentric remodeling and irreversible ventricular stiffening. Initiating endurance training late in life fails to improve ventricular compliance and diastolic function, whereas lifelong exercise training preserves youthful ventricular compliance and prevents age-associated remodeling.
Why it matters
The review highlights that cardiac plasticity declines with age, meaning late-life exercise cannot reverse established myocardial stiffening, whereas lifelong exercise preserves youthful cardiac compliance.
Limits
This is a narrative review with no primary data, sample sizes, or quantitative effect sizes reported in the abstract. Specific modulators such as biological sex, age thresholds, genetic factors, and deep-space environmental stressors remain uncharacterized.
Cited by
- context One year of intensive endurance training in healthy 70-year-old sedentary adults improved cardiorespiratory fitness but failed to alter heart structure or compliance.