A new study suggests that sending people to Mars could be more achievable than once thought. Researchers from Northwestern Medicine, UT Southwestern Medical Center, and UTHealth Houston followed 13 astronauts during six-month stays on the International Space Station.
The study, published inthe Journal Circulation, is the first to examine how the human heart responds to Martian gravity after a long period of weightlessness.
One of NASA’s main worries when planning missions to Mars is whether astronauts’ hearts can handle moving from deep space’s microgravity to Mars’s gravity, which is about one-third as strong as Earth’s.
In the past, astronauts coming back to Earth often had orthostatic hypotension, which is a sudden drop in blood pressure when standing up. This causes dizziness and lightheadedness because being in space reduces muscle and heart mass. But in this study, most astronauts avoided these problems by following NASA’s Exercise Countermeasures program.
To stay healthy in space, the astronauts worked out for up to two hours each day. Their routine included 30 to 45 minutes of endurance training and 60 to 75 minutes of resistance exercises. Dr. James Thomas, a cardiology professor at Northwestern University Feinberg School of Medicine and the study’s senior author, said these results give strong reason to think astronauts can go to Mars and work well there.
Dr. Thomas worked with Dr. Benjamin Levine and Dr. Michael Bungo to study ultrasound heart scans, called echocardiograms, taken before, during, and after each mission. The astronauts scanned each other every few weeks while in space, with Dr. Thomas guiding them live from Earth, sometimes as early as 3 a.m.
During their first two weeks in space, the astronauts’ hearts pumped less blood and filled less than usual. However, their heart function slowly returned to normal as the mission went on.
After returning to Earth, researchers simulated arrival on Mars by tilting the astronauts 22 degrees upward while they lay down, which shifted blood toward their lower bodies. The tests showed no major heart problems, meaning their hearts handled the simulated Martian gravity as well as standing upright on Earth before the mission.