Cardiovascular response of children to 1 hour of microgravity simulation-a pioneering study

This pioneering study investigated cardiovascular responses in children during simulated microgravity exposure using a 15° head-down tilt (HDT) for one hour. Twenty-six healthy participants aged 8-14 years (15 girls, 11 boys) underwent continuous non-invasive monitoring of nine cardiovascular parameters, including heart rate, stroke volume, cardiac output, and blood pressure. Results showed that children tolerated HDT well, with no signs of distress or adverse reactions. Heart rate decreased significantly during tilt, while stroke volume and left ventricular ejection time increased, suggesting adaptive cardiovascular adjustments similar to those observed in adults under microgravity conditions. Cardiac output and cardiac index exhibited transient rises in girls, followed by normalization, and no significant intersex differences were found in blood pressure responses. These findings indicate that children display physiological adaptability comparable to adults, providing novel insights into pediatric cardiovascular function in microgravity analogs and supporting considerations for future inclusion of young participants in space research and tourism.