Down to their very DNA, astronauts\u2019 bodies can change in weird and sometimes significant ways, particularly during a long flight high above the Earth: They start to elongate, often developing a taller \u201cspace height\u201d and because human bodies are mostly liquid, redistribution of fluids may also give them \u201cchicken legs\u201d and a \u201cpuffy head.\u201d Once they\u2019re back, that all starts to readjust. <\/p>\n
Doctors will be keeping all of this in mind as astronauts Barry \u201cButch\u201d Wilmore and Suni Williams return on Tuesday from nearly nine months in space. <\/p>\n
Scientists are still figuring out the long-term health effects of spending a lot of time in space, but decades of data show that astronauts undergo physical changes after even a brief period. Most of those changes will reverse themselves shortly after they return to Earth. <\/p>\n
\u201cThere is some individual variability on how quickly they recover, but it is pretty impressive to see how they will turn the corner and really adapt quickly,\u201d Dervay said. \u201cOftentimes, if you look at them a couple days later, you really have no idea what they\u2019ve just done for the last several months.\u201d <\/p>\n
Microgravity is behind many of the changes that astronauts can experience. <\/p>\n
Without the pull of Earth, astronauts can lose bone density, and their muscles begin to waste away. They can lose motor control, coordination and balance in space, developing a kind of motion sickness, studies show. A lack of gravity can also affect their immune and cardiovascular systems, their vision and their very DNA. <\/p>\n
Most of the effects seem to be short-lived \u2014 only a handful of health issues have so far been found to linger \u2014 and the astronauts can look forward to a lot of rehab exercises on Earth to get their bones and muscles back into shape. <\/p>\n
Although Wilmore and Williams weren\u2019t initially expected to stay on the International Space Station as long as they did \u2013 their initial trip was supposed to last only eight days \u2013 NASA leaders don\u2019t believe the two will have any unusual health problems because of it. <\/p>\n
\u201cWe don\u2019t see any need for any special precaution,\u201d Dina Contella, deputy manager of NASA\u2019s International Space Station Program, said Friday. \u201cLike any astronauts coming back, there is an acclimation period, and so that will vary by crew member.\u201d <\/p>\n
Without gravity for the body to move against and with the body exposed to radiation in space, muscle atrophy and dysfunction can happen to even the fittest astronaut. NASA has found that astronauts\u2019 bodies can experience one-third reduction in muscle fiber size in less than two weeks. <\/p>\n
In a single month in space, an astronaut might also lose up to 1.5% of their bone mass \u2013 about as much as a postmenopausal woman who is not in treatment loses in about a year. Such loss can make people vulnerable to fractures and lead to premature osteoporosis, but more research is needed to learn whether the bone loss persists long after the space flight. <\/p>\n
To help mitigate bone and muscle problems, astronauts eat a special diet and do about 2\u00bd hours of exercise daily, on average. They can use a treadmill or a stationary bike, but they also have a special Advanced Resistive Exercise Device that mimics weightlifting on Earth. <\/p>\n
\u201cWe try to keep the bone strong and muscles strong to minimize any effects of microgravity,\u201d Dervay said. \u201cPlus, from a psychological perspective, it\u2019s outstanding because it gives them that break during the day, and they know they\u2019re doing something for themselves.\u201d <\/p>\n
NASA has been researching whether aerobics and resistance exercises would be as helpful as a treadmill, since the spacecraft needed for future long-distance flight may not be able to accommodate heavy exercise equipment. <\/p>\n
Dervay says the body is \u201cbrilliant\u201d in the way it adjusts to microgravity, but \u201cwe want to ensure that when we bring them home, they\u2019re in the best position they can be to return \u2026 and get back into the normal flow of their lives.\u201d <\/p>\n
Astronauts may view one physical change to their bones as a benefit: Without the pull of gravity, a person\u2019s spine straightens, and they grow taller. <\/p>\n
NASA says the height of a crew member can increase 3% over the first three or four days of weightlessness. Astronaut Kate Rubins, for example, went from 5\u20196\u201d to a \u201cspace height\u201d of 5\u20197.\u201d Once back on Earth, though, gravity brings astronauts back down to their regular size. <\/p>\n
Without gravity, fluids shift. Because the body is 70% liquid, that change is felt at multiple levels. <\/p>\n
On Earth, fluids in the body tend to shift downward, below the heart. But in space, fluids flow evenly throughout the body and shift into places they don\u2019t normally accumulate. <\/p>\n
It\u2019s similar to doing a very long handstand: The 1\u00bd gallons of liquid the body carries move upward. Astronauts often say they feel like they have a head cold and develop an issue that some at NASA call \u201cpuffy face syndrome,\u201d \u201cbird legs\u201d or \u201cchicken legs.\u201d The problems typically clear up after about three days on Earth, according to NASA. <\/p>\n
The fluid movement in the body may also cause lingering back problems, regardless of the length of the space flight. One study found that the incidence of a slipped or ruptured disc is 4.3 times higher in astronauts than in terrestrial populations, and the problem typically happens soon after they return to Earth. <\/p>\n
The fluid redistribution issue also seems to affect many astronauts\u2019 vision, a problem NASA has dubbed Spaceflight Associated Neuro-Ocular Syndrome. The eye flattens due to fluid redistribution, the retinal nerve fiber layer can thicken, and there is a refractive shift so the vision can blur in space. <\/p>\n
Dr. Michael Harrison, an aerospace medicine specialist at Mayo Clinic in Florida, says it\u2019s a bit like using a projector and moving it a few inches closer to the wall. <\/p>\n
\u201cThe picture is going to get a little fuzzier,\u201d he said. \u201cIt\u2019s a major topic because we don\u2019t know an awful lot about it yet.\u201d <\/p>\n
The problem seems to be more common with longer space flights. <\/p>\n
\u201cThe question that is on everybody\u2019s mind is, what happens when we go deeper into space for longer periods of time? Does it plateau, or is this something continues to progress?\u201d Harrison said. <\/p>\n
Not everyone\u2019s vision remains changed. One study found globe flattening in about 16% of astronauts post-flight. <\/p>\n
\u201cSome folks come back and do have what appears to be \u2013 maybe not necessarily permanent changes but chronic changes in vision and requires glasses. Others don\u2019t have it. It\u2019s a fairly new phenomenon,\u201d Harrison said. <\/p>\n
To study the phenomenon, the crew of the five-day commercial flight Polaris Dawn wore special contact lenses last year to measure and collect data on the pressure in their eyes. <\/p>\n
NASA has also developed special \u201cspace anticipation glasses\u201d that are kept at the International Space Station. The glasses are adjustable and mitigate some of the blurriness. <\/p>\n
Fluid in the brain tends to shift in space as well, from the top of the brain to the base. Studies of astronauts after they return to Earth have found that this shift can enlarge parts of their brains called ventricles, even beyond what can typically be seen with normal aging. <\/p>\n
However, MRIs of the crew of the Polaris Dawn mission didn\u2019t find any concerning findings with their brains. <\/p>\n
Time in space can weaken a person\u2019s immune system and make astronauts more susceptible to infections. The white blood cells that help the body fight infections seem to change. <\/p>\n
\u201cIn space, there\u2019s been activation of some latent viruses that folks carry but no health effects associated with that long-term,\u201d Harrison said. <\/p>\n
Space also seems to chemically modify a person\u2019s DNA. On the International Space Station, astronauts wear dosimeters to record their radiation exposure, since it can damage DNA and raise the lifetime cancer risk <\/p>\n
It\u2019s not totally clear what effects other chemical changes to the DNA might have. A study that compared data during and after astronaut Scott Kelly\u2019s mission to space against data from his identical twin brother, retired astronaut Mark Kelly, found that there were chemical modifications to both men\u2019s DNA, but both returned to normal when they returned to Earth. <\/p>\n
Telomeres, the repetitive sequences at the end of a chromosome that protect it from deteriorating, typically decrease with age, but Scott\u2019s telomeres actually increased while he was in space. When he came back to Earth, they shortened again. Scientists say Scott\u2019s telomeres may have been positively affected by his better exercise and diet routine in space. <\/p>\n
Even before they come home, Williams and Wilmore will have increased their fluids using salt tablets and water to try to get back some of what they lost during the early phase of space flight, Dervay said. They also put on garments like compression socks that stretch from the feet to above the waist to move fluid back to the centers of their bodies. <\/p>\n
\u201cEvery crew that comes back comes through a fluid loading protocol, just to make sure when they get back that their body is conditioned properly,\u201d Steve Stitch, manager NASA\u2019s commercial crew program, said Friday. \u201cThere\u2019s nothing beyond what we\u2019ll normally do.\u201d <\/p>\n
The astronauts do not return to their families right away after they splash down. Return-to-Earth protocols include keeping the crew at Johnson Space Center in Houston for several days before the flight surgeons give them the OK to go home. <\/p>\n
\u201cAlmost every organ system in the body is impacted to some degree \u2013 whether it\u2019s the skin, the neurovestibular, the bone, muscle, the immunological system, the cardiovascular system \u2013 so we have programs that our Human Health and Performance team focuses on to try and make sure that we\u2019re covering all those areas,\u201d Dervay said. <\/p>\n
Scientists monitor all astronauts\u2019 health from the time they start training until long after they retire, but as more people spend more days in space, researchers are gaining a much better understanding of what effect it can have on human health in the long term. It\u2019s knowledge that will be essential as government and commercial space programs aim to send humans for extended stays on the Moon and Mars. <\/p>\n
When astronauts return to Earth, their rehabilitation program may involve a series of physical exercises to increase bone density and strengthen muscles. They also do cardiovascular exercises to strengthen their heart muscle, since it doesn\u2019t have to pump as hard in zero gravity as it does on Earth. Additionally, there are exercises to improve coordination to help prevent injuries. <\/p>\n
\u201cGravity is really, really tough,\u201d Wilmore told Cooper. <\/p>\n
Williams said she usually gets her fast-twitch muscles back and her inner ear adjusts in about 24 to 48 hours after returning to Earth. She appreciates the quick physical improvements, but they\u2019re also a little bittersweet. <\/p>\n
\u201cThat will be a little bit sad when [the dizziness] goes away, just because that means that really, physically, the space flight came to an end,\u201d she told Cooper. <\/p>\n
For at least some astronauts, mental health may have the biggest effects. They often experience the \u201coverview effect.\u201d <\/p>\n
\u201cThey get this profound experience that then influences their views on things when they return to Earth,\u201d Harrison said. <\/p>\n
Astronauts describe seeing the world from above as \u201cbeautiful\u201d and \u201cfragile.\u201d It is a world without borders or boundaries, and seeing it causes some to feel an increased sense of connection to others. <\/p>\n
\u201cI\u2019m not going to necessarily use the word \u2018magical,\u2019\u201d Harrison said, \u201cBut it is a very profound philosophical experience being in space.\u201d <\/p>\n<\/p>\n
Down to their very DNA, astronauts\u2019 bodies can change in weird and sometimes significant ways, particularly during a long flight high above the Earth: They start to elongate, often developing a taller \u201cspace height\u201d and because human bodies are mostly liquid, redistribution of fluids may also give them \u201cchicken legs\u201d and a \u201cpuffy head.\u201d Once …<\/p>\n","protected":false},"author":1,"featured_media":2120,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"loftocean_post_primary_category":0,"loftocean_post_format_gallery":"","loftocean_post_format_gallery_ids":"","loftocean_post_format_gallery_urls":"","loftocean_post_format_video_id":0,"loftocean_post_format_video_url":"","loftocean_post_format_video_type":"","loftocean_post_format_video":"","loftocean_post_format_audio_type":"","loftocean_post_format_audio_url":"","loftocean_post_format_audio_id":0,"loftocean_post_format_audio":"","loftocean-featured-post":"","loftocean-like-count":0,"loftocean-view-count":570,"tinysalt_single_post_intro_label":"","tinysalt_single_post_intro_description":"","tinysalt_hide_post_featured_image":"","tinysalt_post_featured_media_position":"","tinysalt_single_site_header_source":"","tinysalt_single_custom_site_header":"0","tinysalt_single_custom_sticky_site_header":"0","tinysalt_single_custom_sticky_site_header_style":"sticky-scroll-up","tinysalt_single_site_footer_source":"","tinysalt_single_custom_site_footer":"0","footnotes":""},"categories":[35],"tags":[],"class_list":["post-2119","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-health-news"],"_links":{"self":[{"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/posts\/2119","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/comments?post=2119"}],"version-history":[{"count":0,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/posts\/2119\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/media\/2120"}],"wp:attachment":[{"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/media?parent=2119"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/categories?post=2119"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/retirednurseblog.com\/index.php\/wp-json\/wp\/v2\/tags?post=2119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}