Ever since the early 1960’s from the Gemini space missions, the loss of skeletal muscle mass in response to microgravity exposure has been a major physiological concern. As I mentioned in my last post, the absence of gravity – or “loading” as is more routinely referred to – causes the muscles that are responsible for keeping us upright to lose some of their mass. This is termed muscle atrophy and is primarily because they have nothing to interact with; nothing to work against. Every day, our leg, hip and back muscles save us from toppling over when assuming the standing position. In space, there is no such thing as the standing position, because there is no “floor” or anything to stand against.
The term cardiovascular means heart (cardio) and blood vessels (vascular). They work together in a synergistic and complimentary fashion to ensure adequate oxygenated blood supply to the entire body. There are many different factors that can influence how that happens, gravity being one.