Astronauts' hearts pass simulated Mars gravity test

Researchers from Northwestern Medicine, UT Southwestern and UT Houston monitored the hearts of 13 astronauts who spent about six months on the ISS. After returning to Earth, the astronauts showed no significant cardiovascular strain under simulated Martian gravity, a 22-degree tilt. Daily exercise of up to two hours helped preserve heart function.

• 13 astronauts spent about six months on the ISS under cardiology monitoring
• Crews exercised up to 2 hours daily: 30–45 min endurance and 60–75 min resistance training
• Hearts handled simulated Martian gravity (38% of Earth's) with no significant strain
• Cardiac filling and stroke volume dipped in the first two weeks, then recovered