Astronauts’ hearts just passed a surprising test for Mars
A new study tracking 13 astronauts suggests that the human heart may be surprisingly well equipped for a journey to Mars, especially with regular exercise during spaceflight. Researchers found that astronauts' hearts adapted to months of weightlessness and handled simulated Martian gravity without major problems, offering new hope for future missions to the Red Planet.
Key points
- A study of 13 astronauts who spent about six months on the International Space Station found their hearts adapted to weightlessness and performed well under simulated Martian gravity.
- Daily exercise of up to two hours, including endurance and resistance training, helped maintain cardiovascular health during spaceflight.
- Researchers say the findings offer encouraging evidence that humans could endure a journey to Mars and work on its surface.
A new study suggests the human heart can adapt well to months of weightlessness, offering encouraging evidence that astronauts could endure a long journey to Mars. Researchers from Northwestern Medicine, UT Southwestern and UT Houston monitored 13 astronauts who spent approximately six months aboard the International Space Station.
The study, published last month in the journal Circulation, is the first to investigate how the heart responds to simulated Martian gravity after an extended period in space. NASA has been concerned about how astronauts' hearts and circulatory systems would react to Martian gravity, which is only about one-third as strong as Earth's.
Exercise and heart adaptation
Echocardiograms taken before, during and after the missions showed that the astronauts' hearts initially struggled in space. During the first two weeks, researchers observed declines in cardiac filling, stroke volume and other measures of cardiovascular performance. Over time, these measures gradually improved, approaching pre-launch levels.
Intensive daily exercise played an important role. As part of NASA's Exercise Countermeasures program, astronauts exercised for up to two hours each day, including 30 to 45 minutes of endurance training and 60 to 75 minutes of resistance training.
With our findings, there is now reason to think that we would be able to traverse to Mars, get there and actually work on the surface of Mars
— Dr. James Thomas
Simulated Mars gravity test
After returning to Earth, each astronaut was tilted upward by 22 degrees from a lying position to approximate the circulatory effects of Martian gravity. The astronauts' hearts performed just as well under this simulation as they had when standing upright on Earth before their missions, with no significant signs of cardiovascular strain.
The researchers noted the findings come from a relatively small group and a simulation rather than an actual Mars landing, but said they provide valuable evidence for planning future missions.
