Scientists discover going to Mars could break human hearts

Key Points:

• A study by the Medical College of Wisconsin found that deep-space radiation exposure may cause progressive heart damage, weakened immune defenses, and genetic changes linked to cardiovascular problems, raising concerns for astronauts on long Mars missions.
• Researchers simulated Mars mission conditions using rats exposed to hindlimb unloading to mimic microgravity and cosmic radiation at NASA’s Space Radiation Laboratory, then monitored them for up to a year to observe delayed effects.
• Radiation caused perivascular fibrosis in rat hearts, with scar tissue doubling by 270 days post-exposure, potentially restricting blood flow and increasing heart attack risk; this damage worsened over time and was not significantly influenced by simulated weightlessness.
• The radiation exposure also led to a significant, lasting reduction in natural killer immune cells and genetic mutations associated with increased risks of blood cancers and cardiovascular disease, suggesting accelerated aging effects.
• Limitations include the study’s single intense radiation dose, use of only male rats, and uncertain applicability to humans, but findings emphasize the need for improved radiation protection and further research for safe human Mars exploration.