Does the shape of the heart change during space travel?

“Does the astronaut’s heart have the same shape and rhythm in space?” , Ask the November National on our page FB. That’s our reader’s question for the week. Thanks everyone for your input.

In space, the core becomes round

In weightlessness, the heart rate will not be modified. However, the shape of the astronauts’ heart changes: it becomes round! This is detected An American study presented in 63^e American College of Cardiology annual meeting in March 2014. To come to this conclusion, the team of Dr. James Thomas, chief scientist for cardiac imaging and ultrasound at NASA, examined data collected by 12 NASA astronauts as they passed by the International Space Station (ISS). The astronauts were trained to use an ultrasound machine to take pictures of their hearts when they were on board, and they took pictures before, during, and after their stay aboard the International Space Station.

The verdict: Their heart is approximately 10% lower in weightlessness. This transformation turned out to be similar to what the scientists had predicted with a mathematical model developed for this project. This change in heart shape is due to the effects of microgravity on the physiology of the heart during extended periods spent in space. Astronauts can actually survive for months in weightlessness aboard the International Space Station. However, in the absence of the force of gravity, the cells of an organism are less constrained. This radically different environment can be affected by its organization and stability based on correlation with Earth’s gravity. The balance is broken, the cells are racing.

loss of muscle mass

“The heart doesn’t put in as much effort in space, which can lead to a loss of muscle mass.”, explained in 2014 by Dr. James Thomas. The heart, which is a muscle, works less because it no longer has to compensate for the force of attraction. “This could have serious consequences after the astronauts return to Earth and we are looking for solutions, including exercises to prevent or prevent this phenomenon.”

The researchers say that the spherical shape that astronauts’ hearts took on in space soon disappeared shortly after they returned to Earth. But this twisting of the heart in microgravity may mean that it works less efficiently, although the lasting effects of this phenomenon on heart health are still unknown.

However, in 2016, another American study showed that the Apollo astronauts had a significantly higher cardiovascular mortality rate than their colleagues who performed missions in low Earth orbit or who did not make a trip to Earth. because of : Exposure to ionizing radiation from the space environment.