Space Travel Changes Astronauts Heart Shape, Makes It More Spherical
Space -- the final frontier, every astronaut's dream destination. But with this dream comes associated health risks, like the astronauts' bones and muscles get weak due to the gravity-free environment. New findings also suggest that long periods of microgravity in space results in the heart becoming more spherical, which can lead to cardiac problems. This study conducted on 12 astronauts is to be presented at the American College of Cardiology's 63rd Annual Scientific Session.
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Considering that NASA plans to put astronauts on Mars by 2030, this research is an important step to understand how an 18 month or longer space trip to the red planet would affect the astronauts' health."The heart doesn't work as hard in space, which can cause a loss of muscle mass," said James Thomas, M.D., Moore Chair of Cardiovascular Imaging and Lead Scientist for Ultrasound at NASA, and senior author of the study. "That can have serious consequences after the return to Earth, so we're looking into whether there are measures that can be taken to prevent or counteract that loss."
Astronauts routinely workout to help maintain their physical and mental strength. Knowing the amount and type of exercise that they need to perform to keep their heart healthy on a long space flight is paramount. The exercise regime followed by astronauts can also be followed by ordinary people to maintain a healthy heart. It's especially beneficial to people with severe physical limitations such as people on extended bed rest or those with heart conditions.
The research team trained astronauts to take images of their hearts using ultrasound machines installed on the International Space Station. Twelve astronauts participated, providing data on heart shape before, during and after spaceflight.
The tests showed that in space, the heart becomes more spherical by a factor of 9.4 percent. This corroborated with the results obtained by applying mathematical models, which were developed for the project. These models can also be used for a better understanding of cardiovascular diseases affecting patients on Earth.
"The models predicted the changes we observed in the astronauts almost exactly. It gives us confidence that we can move ahead and start using these models for more clinically important applications on Earth, such as to predict what happens to the heart under different stresses," Thomas said.
The team is now working to generalize the models to analyze such conditions as ischemic heart disease, hypertrophic cardiomyopathy, and valvular heart disease. "The models could help us simulate those pathologies to understand the impact on cardiac function," Thomas said.
But the heart shape of the astronauts' returns to normal once they are back on Earth. The more spherical change in the heart shape in outer space could mean that the heart is not functioning as usual. Whether this change in heart shape has long term implications on health, is as yet unknown.
The research team aims to understand the different cardiovascular conditions that astronauts experience like orthostatic hypotension, where astronauts upon return to Earth, commonly become lightheaded or pass out. This happens because the body experiences a sudden drop in blood pressure when standing up. Arrhythmias, a problem related to the rate or rhythm of the heartbeat is also commonly observed in space travel while radiation exposure in space may result in atherosclerosis.
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