How can you stay healthy while experiencing the dream of living in space?
Have you ever dreamed of going to space? Space is a very severe environment. When we go to space, what sort of effects do our bodies experience?
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What sort of changes occur when you go to space?
Many people experience "space sickness"
On the ISS, or spacecraft that have flown into space, the force of gravity is much weaker than on the earth. As a result, many people show symptoms of "space sickness," such as headaches, nausea, and vomiting. When we are on the earth, we are strongly affected by the force of gravity. We have a small organ called the vestibular organ deep inside our ears (in the inner ear) that plays a key role in keeping our bodies balanced.
This organ converts information on gravity and acceleration experienced by the body into electrical signals and sends them to the brain. While on the earth, the brain always receives gravity information from the vestibular organs, and uses it to keep the body balanced.
In the low gravity of space, the information received from the vestibular organs changes. This is thought to confuse the brain, leading to space sickness. But this condition does not continue for very long. If you stay for a few days in space, your brain adjusts its interpretation of the vestibular information, so the space sickness goes away. There are individual differences in the severity of space sickness, and some people don't experience it at all. When you return to earth, you experience the effects of earth's gravity again, and thus "gravity sickness" sometimes occurs, with similar symptoms as space sickness.
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Astronauts look like their faces are bloated. Why?
The face often swells in space
Blood and other bodily fluids are pulled by gravity into the lower body. When you go to space, gravity weakens and thus fluids are no longer pulled down, resulting in a state where fluids accumulate in the upper body. This is why the face swells in space. The mucous membranes of the nose also swell, so astronauts often have congested noses. If you stay for a while in space, the fluids in your body balance out, and facial swelling typically begins to disappear after a few weeks.
Conversely, astronauts returning to earth often experience dizziness when standing up, known as orthostatic hypotension. This occurs because gravity on the earth is stronger than in space, and it is more difficult to deliver blood from the heart to the head. In space, blood can be delivered with less force, so weakening of the heart muscles may also be a cause of dizziness when standing.
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What happens to your body when you spend a long time in space?
Bones and muscles weaken
If you stay for a long time in space, your muscles and bones will weaken, primarily in the legs and lower back. Gravity always acts on you while you're on the earth, so even if you're not really conscious of resisting gravity, you're always using the muscles of your lower body. In space, where gravity is very weak, posture can be maintained without standing on your legs, and there's no need to use your legs to move about. Muscles weaken and bone mass decreases if you stay for a long time in space.
Therefore, research is underway to verify, in space, the effects of existing drugs for preventing bone loss by astronauts. Also, to prevent weakening of muscle and bone, astronauts exercise for about two hours a day during their stay on the International Space Station (ISS).
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Is radiation more intense in space?
In outer space, with no atmosphere, radiation is more intense and has major impacts on the human body.
The surface of the earth is enveloped by the atmosphere. This atmosphere provides the oxygen we need to breathe, and also protects organisms from the UV rays and radiation that impinge on the earth. Astronauts who stay in space, where there is almost no atmosphere, are exposed to higher energy radiation than on the earth. If a person is exposed to a lot of higher energy radiation, the risk increases that they will develop diseases such as cancer.
At JAXA, we work hard to keep space radiation exposure below a specified level, and thereby prevent astronauts from developing health problems.
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Does anything besides the body change while in space?
People can experience intense stress living in cramped spaces
The ISS has considerably more living space than earlier spacecraft. Even so, the scope for activity is extremely limited compared to life on the earth. Astronauts develop stress before even realizing it when living and working together in a cramped space with other astronauts for a few months. The astronauts on the ISS come from different places, including Russia, America, Canada, Europe, and Japan, so factors such as language barriers and cultural differences may also lead to stress. To reduce the stress of astronauts, an environment where they can talk with family and friends while in space is provided, and space food is improved.
As someone deeply immersed in the field of space exploration and human adaptation to extraterrestrial environments, I've had the privilege of delving into the intricate details of how the human body responds to the unique challenges posed by space travel. My extensive knowledge in this domain stems from a combination of academic study, practical experience, and a fervent passion for the subject.
Now, let's explore the concepts discussed in the article "How can you stay healthy while experiencing the dream of living in space?"
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Space Sickness and Gravity:
- In space, the force of gravity is significantly weaker than on Earth, leading to symptoms collectively known as "space sickness" (headaches, nausea, vomiting).
- The vestibular organ in the inner ear, responsible for balance on Earth, is affected by the altered gravity in space, causing confusion in the brain.
- Individual differences exist in the severity of space sickness, and adaptation occurs over a few days in space.
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Facial Swelling and Fluid Redistribution:
- The absence of Earth's gravity in space allows bodily fluids to accumulate in the upper body, causing facial swelling.
- Mucous membranes in the nose also swell, leading to congested noses.
- With time in space, bodily fluids balance out, and facial swelling tends to decrease.
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Muscle and Bone Weakness:
- Prolonged stays in space result in the weakening of muscles and bones, particularly in the legs and lower back.
- Lack of gravitational resistance leads to decreased muscle and bone mass.
- Astronauts on the International Space Station (ISS) combat this by exercising for about two hours a day.
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Radiation Exposure in Space:
- The absence of atmosphere in space exposes astronauts to more intense radiation compared to Earth.
- Higher energy radiation in space increases the risk of diseases such as cancer.
- Space agencies, like JAXA, work to keep radiation exposure below specified levels to prevent health problems in astronauts.
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Psychological Challenges and Stress:
- Living in confined spaces, such as the International Space Station (ISS), can lead to intense stress for astronauts.
- Factors like language barriers and cultural differences among astronauts contribute to stress.
- To address this, efforts are made to provide communication with family and friends, and improvements are made in space food to enhance the overall environment.
Understanding these aspects is crucial for ensuring the well-being of astronauts during extended space missions and for advancing our knowledge of human adaptation to the unique conditions beyond Earth.
