Space Can Make Your Blood Flow Backwards
BGR | 11/15/2019 | Mike Wehner

The paper, which was published in JAMA, examined the circulatory changes that took place in 11 different space travelers that spent time aboard the International Space Station.

It found that while blood flow was perfectly normal when the scientists left Earth, dramatic changes had already begun by their 50th day in space.

In particular, circulation changes through the head and brain raised some serious concerns.

In seven of the space travelers, blood flowing from the head down to the rest of the body showed signs of stagnation and, in some cases, even reversal.

On Earth, gravity aids in draining blood from the head and ensuring a steady flow. In space, that assistance just isn’t there, and slow-moving or stagnant blood can cause clotting.

In fact, two of the crew members were found to have clots or partial clots in their left internal jugular vein.

Blood clotting is incredibly dangerous when it happens within the body, and if a clot were to form and then travel to the lungs it could create a pulmonary embolism, which is a potentially fatal condition that requires immediate treatment.