Learn about the zero gravity life of astronauts and the impact of the lack of gravity on the human body.
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Gravity hurts you can feel it hoisting a loaded bag back or pushing a bike up a hill. But lack of gravity hurts too, when astronauts return from long terms things in space, they sometimes need to be carried away in stretches. Gravity is not just a force, it’s also a signal. Signal that tells the body how to act, for one thing it tells muscles and bones how strong they must be. In zero G muscles atrophy quickly, because the body perceives it doesn’t need them. The muscles use to 5 gravity like those in the cabs and spine which maintain posture can loose around 20% of their mass if you don’t use them. Muscle mask can vanish at a rate as high as 5% a week. The bones the loose can be even more extreme, bones in space atrophy at the rate of about 2% a month. Models suggest that the total lost could reach 40-60%. Blood feels gravity too, on Earth blood pulls in the feet. When people stand the blood pressure in that feet can be high about 200 mm of mercury. In the brain though it’s only 60-80mm mercury. In space whether familiar pull of gravity is missing, the head to toe gradient vanishes. Blood pressure equalizes and becomes about a hundred millimeters of mercury throughout the body. That’s why astronauts can look ode, that faces filled up with fluid pop up and their legs which can loose about the literal fluid each then out. But that shifting blood pressure also senses signal, bodies expect a blood pressured gradient. High blood pressure in the head raises in along the body has too much blood. Within 2-3 days of weightlessness astronauts can loose as much as 22% of their blood volume as a result of that aren’t message. This change affects the hot too, if you have less blood explains Dr. Victor Schneider researched medical office of the NASA headquarters then your hat doesn’t mean to pamper hot, it’s going to atrophy. The question is, do such looses matter? Well perhaps not of you planned to stay in space forever, but eventually astronauts return to Earth and the human body has to re adjust to the relentless pull of gravity. Most space adaptations appear to be reversible. But the re building process is not necessarily an easy one. Each of the parameters has their own normal recovery time. Blood volume for example is typically restored within a few days. Astronauts get thirsty when they come back because their body says you don’t have enough blood in your blood vessels. And that causes the messengers to say “drink more” also; the body doesn’t urinate as much. Muscle too can be recoup most comes back within a month or so. Although it might take longer to recover completely. We normally say that it takes a day of recovery on Earth each day that somebody is in space. Bone recovery though has proven problematic. For about three to six month space flight it might require 2-3 years to regain lost bone if it’s going to come back. In some studies have suggested that it doesn’t, you really have to exercise a lot. According to Dr. Alan Hogans recently have NASA aims and now professor of orthopedics of the University of California San Diego medical school. It’s important to keep astronauts in good physical condition. We want the crew members to function normally when they come back to Earth. And not have to lie around for long periods of rehabilitation. And Earth isn’t the only planet that astronauts might visit. One day humans will journey to Mars the six month trip in 0 G before they disembark on a planet with 38% of Earth’s gravity. Well have to maintain those astronauts to the very high level of fitness. When they get to Mars they won’t be anyone to help them if they get into trouble. They’ll need to be able to handle everything themselves. Exercise is the key, but exercising in space differs from exercising in Earth. Here gravity is pull automatically provides the resistive force that maintains muscles and bones. In space even if you do the same amount of work that you were doing down here on Earth. You’ve missed that gravity component
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