Maria Imran 
Entering the world of Mars mission heart risks might take its toll on the human heart. Researchers have uncovered new information on the damage that deep space radiation can inflict on blood vessels close to the heart, which has implications for Mars mission heart risks. The research doesn’t prove that humans can’t live while they are on Mars. Rather, it is setting a red flag, showing a danger that scientists need to be aware of before astronauts can leave the planet for years.
What did the study find?
The study, published on 30 September 2026 in PLOS One, looked at 72 male middle-aged rats, not humans. Researchers simulated parts of spaceflight on Earth by injecting high-energy particles into the rats that simulate galactic cosmic rays. Researchers simulated parts of spaceflight on Earth by injecting high-energy particles into the rats that simulate galactic cosmic rays. In addition, some rats had their hind legs suspended to simulate some of the effects of weightlessness. Animals were followed for months following exposure.
Of rats receiving 0.75 gray (Gy) of simulated radiation (the dose the researchers believe would be seen in a planned three-year mission to Mars), 83% developed fibrosis around the blood vessels in the heart after 360 days. Fibrosis is the build-up of scar-like tissue. The rate for the higher dose of 1.5 Gy reached 100% after 270 days. This tissue may constrict blood vessels leading to the heart, increasing the risk for cardiovascular disease.
Most of the effects were associated with radiation. There was no scarring in the hearts of the weightless animals, and the simulated weightlessness did not increase the scarring at the higher radiation dosage. They also discovered that the immune system cells were changing, including a reduction in immune system cells called natural killer cells in the spleen that recognize abnormal cells.
Why Mars travel raises concern
Earth’s magnetic field and atmosphere shield people from much of the radiation in space. Beyond this protection, astronauts face galactic cosmic rays that can pass through spacecraft shielding. A Mars mission would keep crews in deep space for long periods, where both radiation exposure and low gravity can affect health. NASA identifies space radiation as a serious risk for future Mars crews.
Does this mean humans cannot go to Mars?
No. The findings came from rats, and the experiment delivered radiation over a short period rather than gradually over a real mission. The researchers also did not directly measure how well the hearts pumped blood. The results cannot predict whether or how badly human astronauts would be affected.
The study adds to the case for better shielding, radiation monitoring and medical countermeasures before crewed deep-space travel becomes routine. Mars remains a difficult destination, but this research is a warning- not a verdict. Protecting the heart may be as important as building the rocket.
