Cardiac adaptations to 60 day head‐down‐tilt bed rest deconditioning. Findings from the AGBRESA study

Aims Reduced physical activity increases the risk of heart failure; however, non‐invasive methodologies detecting subclinical changes in myocardial function are not available. We hypothesized that myocardial, left ventricular, systolic strain measurements could capture subtle abnormalities in myocardial function secondary to physical inactivity. Methods and results In the AGBRESA study, which assessed artificial gravity through centrifugation as potential countermeasure for space travel, 24 healthy persons (eight women) were submitted to 60 day strict −6° head‐down‐tilt bed rest. Participants were assigned to three groups of eight subjects: a control group, continuous artificial gravity training on a short‐arm centrifuge (30 min/day), or intermittent centrifugation (6 × 5 min/day). We assessed cardiac morphology, function, strain, and haemodynamics by cardiac magnetic resonance imaging (MRI) and echocardiography. We observed no differences between groups and, therefore, conducted a pooled analysis. Consistent with deconditioning, resting heart rate (∆8.3 ± 6.3 b.p.m., P