Since there's no gravity in space, it poses a challenge for our heart because there's no force to pull blood into the lower part of the body. Instead, blood goes to the chest and head, causing astronauts to have puffy faces and bulging blood vessels in their necks.
Every time we stand up, gravity pulls blood into parts of the body that are below the heart; the heart which acts as a pump evolved in the presence of gravity. A simple experiment you can do to prove this is to let your hand hang down for a short time then examine the veins in the back of your hand. These veins will get bigger because they are full of blood. But raise your arm above your head, and these veins, emptied of blood, disappear.
Furthermore, research shows that direct physical contact of the human body with the surface of the
earth (called
grounding or
earthing) also has positive effects on human physiology and health.
In this study, they found that
grounding increases the surface charge on RBCs and thereby reduces blood viscosity and clumping. Now they didn't use data within a gravity-less apparatus, but I don't see any reason why it wouldn't apply to an astronaut either. A segment from the study which I found interesting reads:
The branch of physics known as electrostatics teaches that, when two conductive objects with different electrical potential touch each other, there is a virtually instantaneous transfer of charge so that the two objects equilibrate to the same electrical potential. The human body is a conductor of electricity and so is earth (soil), except in very dry areas such as deserts.
Consequently, grounding leads to rapid equalization of the electrical potential of the body with the potential of the Earth (planet) through an almost instantaneous transfer of electrons from soil to the body. This has been the natural bioelectrical environment of the human body and of other organisms throughout most of evolutionary history.
Quick Reply
