"Our bodies love force," said John DeWitt, a senior biochemist who works as a contractor for NASA and focuses on crew health. "Force is what helps our muscles get stronger, force is what helps our bones to stay strong, force is what helps, or heart to stay strong by having to pump blood against gravity. and a sudden loss of a really important stimulus that's important for health. "
After more than 50 years of human spaceflight, researchers know some of the risks posed to the human body in zero gravity. Space motion sickness occurs in the first 48 hours, creating a loss of appetite, dizziness and vomiting.
Over time, astronauts staying for six months on the International Space Station can experience the weakening and loss of bone and atrophying muscles. They also experience blood volume loss, weakened immune systems and cardiovascular deconditioning because floating takes little effort and heart does not have to work hard to pump blood.
Scott Kelly and other astronauts in their late 40s and 50s have also complained about their vision being slightly altered.
"You can lose a percentage of bone mass each month, and that's the typical situation astronauts are in," astronaut Mark Kelly said. "If we want to send people to Mars someday, this is something we're going to have to learn to overcome." If the human body was to stay in space for 10 to 20 years, evolutionarily, over a long period of time, we would probably lose our skeleton in space because you would not need it. "
Exercise was developed as a countermeasure to reduce the amount of bone mass and muscle loss
"We have not flown people on long-duration missions with no exercise," DeWitt said. "We built our exercise suite as time went on. But, in the early Apollo missions, there was no exercise, and one of the things that came back from the Apollo astronauts is, 'hey, you need some kind of exercise device on here. ' "
For any mission longer than eight days, exercise must be provided, DeWitt said.
Scott Kelly spent a year in space, but he followed the exercise regimen and used the machines on the space station. The astronauts who will return to the moon and eventually go to Mars will need exercise capabilities on their spacecraft and within their environment. These are still being developed.
"We have to go in a different direction and build smaller devices, more like all-in-one devices that still have the same capabilities but at the same time "A new study published in Frontiers in Physiology suggests that resveratrol, an antioxidant and compound found in blueberries and the skin of grapes, could be part of the dietary strategy that keeps astronauts strong on Mars. Once they arrive on the Red Planet, astronauts will be dealing with much less gravity than they are used to: about 40% of Earth's gravity.
Weight-bearing muscles like the soleus, located in the calf, bridge conditioning.
"After just three weeks in space, the human soleus muscle will shrink by a third," said lead study author Marie Mortreux of Beth Israel Deaconess Medical Center, Harvard Medical School. "Resveratrol, which has been studied in Alzheimer's disease, has been found to be anti-inflammatory, anti-diabetic and antioxidant." This is accompanied by a loss of slow-twitch muscle fibers, which are needed for endurance. "