A new report from NASA suggests that astronauts would have significant blood flow problems in the upper part of the body (in the head, specifically). The unexpected discovery has important implications for long-duration space missions, including trips to Mars.
It is true thatFor decades it has been documented that spaceflight is quite harsh on the human body,such as the fact that the reduction of gravity (to 0 gravity) causes the muscles to lose mass and the bones to be significantly more fragile. Astronauts also experience loss of blood volume, a weakened immune system, and cardiovascular deconditioning, as floating requires little effort and the heart doesn’t have to work as hard to pump blood.But the new study shows a major problem that we didn’t have: a blood vessel on the side of the neck that is responsible for draining blood from the face, brain and neck.And spending time in space can affect the way blood flows through the internal jugular vein, causing blood to stop or even flow backward, a health risk thatwas unknown until now.
In the space agency study, published in the magazineJAMA Network Open,the scientistsexamined 11 healthy astronauts who had been aboard the International Space Station for an average of six months.During routine ultrasound evaluations, on day 50 of their missions, they discovered thatseven crew members had stagnant or reverse blood flow in the left internal jugular vein.
They also found that an astronaut developed a clot in the internal jugular vein during spaceflight, and another crew member also developed a partial clot after returning to Earth, according to the research.
This is the first time that scientists have observed these conditions in astronauts and the implications of their discovery could affect future long-term space flights, such as the proposal to put humans on Mars in the near future. A manned mission to Mars could take up to four hundred days, even if the mission involves little or no stay on the surface of the Red Planet. In recent times, NASA scientists have also raised concerns about the risk of radiation from energetic particles on long-term space missions.
According to the team responsible for the study, this problem should be investigated before starting to send astronauts on long trips to Mars. It is not yet clear what the consequences of this type of thrombosis could be, but the implications could be serious and even fatal.
“Exposure to a weightless environment during spaceflight results in a chronic change in blood and tissue fluid compared to upright posture on Earth, with unknown consequences for cerebral venous flow, ” the authors state.
Here on Earth, of course, gravity takes over the job of drawing blood from the head to the rest of the body – it’s one of the reasons you’d start to feel very strange if you stood handstand for an extended period of time.
“Fluid shifts to the head during prolonged weightlessness cause facial swelling, decreased leg volume, increased stroke volume, and decreased plasma volume,” the experts continue.
Needless to say , more research is needed to determine how big this problem is and how we might mitigate it in future space flights.
Referencia: Assessment of Jugular Venous Blood Flow Stasis and Thrombosis During Spaceflight. Cardiology. KarinaMarshall-Goebel,PhD1;Steven S.Laurie,PhD1;Irina V.Alferova,MD, PhD2;et al JAMA Netw Open.2019;2(11):e1915011. DOI: doi:10.1001/jamanetworkopen.2019.15011
