The human heart was not meant to pump in space.
Early astronauts in the Apollo program performed every conceivable physical test to ensure that they were each at the pinnacle of human fitness. And yet, when they returned to Earth after just a few days in space, they felt dizzy when standing and tests showed that each beat of their heart pumped less blood than it had before the mission.
A lack of gravity, NASA scientists found, caused the astronaut’s heart to weaken and become deconditioned compared to the effort it must exert in Earth’s gravity. In particular, the muscular pump loses the high-end performance reserve that lets it kick into high gear during a crisis event, when the astronaut’s muscles are screaming for more oxygen-rich blood.
In an effort to improve astronaut safety, Gregory Kovacs, a professor of electrical engineering at Stanford; Laurent Giovangrandi, a senior research engineer; and their lab of graduate and undergraduate students have worked to develop a device that could provide high-fidelity measurements of astronauts’ cardiovascular performance.
“If you’re going to put people on long-term missions in an environment that’s going to alter their physiology, it’s nice to know that you can measure those changes,” said Kovacs, who also has a courtesy appointment in the Stanford School of Medicine.
For the past two years, his group has been testing their diagnostic tool in rarefied air, aboard an airplane that astronauts have affectionately dubbed the “vomit comet.”...