Impact of Prolonged Spaceflight on Cardiac Structure and Function: An Exploratory Longitudinal Observational Study.

Prolonged spaceflight causes transient reductions in cardiac volume and mechanics that stabilize during the mission, with no lasting large changes in cardiac structure or function.

• Why it matters: Understanding how long-duration spaceflight affects the heart is crucial for astronaut health and future Mars missions, yet data on long-term cardiac adaptations are limited.
• What they did: Thirteen astronauts were studied over an average of 164 days using echocardiography preflight, during spaceflight, and postflight, including measurements under simulated Martian gravity.
• The result: Initial microgravity-induced reductions in cardiac volumes and myocardial deformation measures normalized during spaceflight, and after six months, no greater cardiac load was observed in simulated Martian gravity than preflight upright posture, implying minimal long-term cardiac risk.