What Happens to the Human Body in Space

Effect of spaceflight on the human body.
What would space do to the human body?

While researchers are working on thrusters, possibilities for space colonization, and ways to provide water and power in space, other scientists are trying to understand how space affects the human body. Much of their knowledge has now been compiled in a collection of 29 articles that is the result of what is known as The Twins Study, which followed two astronauts.

Video: In the largest study of its kind, scientists are coming closer to understanding exactly how space affects the human body.

What Happens to the Human Body in Space

Between March 2015 and March 2016, NASA scientists studied the metabolism of retired astronauts (and identical twins):

  • Scott Kelly, who lived aboard the International Space Station (ISS),
  • and Mark Kelly, who remained on Earth.
The Kelly brothers: Scott (right) grew a few inches and suffered from a buildup of fluid in his head due to microgravity.
Scott and Mark Kelly. Twins Study | NASA. Source: NASA/Disclosure.

The study reveled what Happens to the Human Body in Space:

  • Bones lose density at a rate of 1.5% per month
  • Space travel shrink the muscles by up to 25%
  • Body fluids accumulate in the upper body
  • and the amount of circulating blood decreases, resulting in decreased oxygen supply to the brain

The data collected came from:

  • Ten studies
  • Conducted by 84 researchers from 12 universities
  • NASA’s Human Research Program

After the Twin study, 56 additional astronauts were monitored to document the effects on them.

NASA Details How Space Affects the Human Body

The external factors affecting humans in space have been studied through an approach referred to as Multiomics.

Multiomics is a biological analysis in which the dataset is drawn from the:

  1. Genome
  2. Proteome
  3. Transcriptome
  4. Epigenome
  5. Metabolome
  6. Microbiome

Determining how they interact and influence each other.

Astronaut Akihiko Hoshide, after collecting blood aboard the ISS
Astronaut Akihiko Hoshide, after collecting blood aboard the ISS. Source: NASA/Disclosure.

In summary, the scientists have identified six key factors that determine what happens to a person’s body in space:

1. Mitochondrial dysregulation

Mitochondria (responsible for generating most of the chemical energy in a cell) work differently.

2. Oxidative stress

The space environment causes an imbalance between free radicals and antioxidants in the body, probably caused by the radiation to which astronauts are exposed.

3. DNA damage

Space radiation can also affect human genes.

4. The length of telomeres

These structures serve to protect the genetic material that the chromosome carries. Over the course of life and up to billions of cell divisions, telomeres shorten until they are so small that they can no longer protect the DNA – the cell then stops reproducing. In space, telomeres lengthen, but they return to their original size when the astronaut returns to Earth.

5. Variations in microbiomes

The genetic material of the microbes that inhabit the human body is altered by the spatial environment.

6. Epigenetic changes

The mechanisms that regulate our DNA (ie, “turn on” and “turn off” sets of genes) react to microgravity.

Astronauts lose calcium in space. What Happens to the Human Body in Space.
The study of the bone health of astronauts in space is being key in the research and development of new treatments for diseases related to bones such as osteoporosis.

Scientists using this data to develop:

  • Preventive measures
  • Treatments
  • Therapies

Understanding How Space Affects the Human Body

As space travel becomes more advanced and humanity gets closer to sending astronauts to Mars – we need to know how our bodies will cope with long-term space travel. And thanks to the largest study ever published on the subject, the picture is now emerging.

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