Have you ever quickly stood up and felt faint or light-headed? The unsettling sensation can be caused by a drop in blood flow to your brain. We have the unique ability to not pass out from dizziness when we lower our head to ground level to drink water and then lift our head up again. Another special way we can control our body has even assisted astronauts with space travel. National Aeronautics and Space Administration (NASA) scientists in the US observed that baby giraffes, to prevent blood pooling in their legs, rapidly thicken or inflate their veins after birth to walk.