The Effects of Space and Microgravity Environment on the Human Body: What We Know So Far
Updated: Aug 3
Since the first human spaceflight in 1961, scientists have been eager to explore the effects of space and microgravity environment on the human body. From the Apollo missions to the International Space Station, many advances have been made in our understanding of how space and microgravity affect the human body.
We now know that exposure to space and microgravity environment can cause a variety of physical and psychological changes, ranging from weakening of bones, muscles and cardiovascular system to changes in vision, mood and sleep.
Further research is needed to understand the long-term effects of space and microgravity environment on the human body, but this article will provide an overview of what we know so far and the challenges that remain.
Overview of Effects of Space and Microgravity on the Human Body
The human body can be exposed to space and microgravity in two ways: being in weightlessness in space and being in reduced gravity due to reduced gravity environments on Earth. Most of the research has been conducted on astronauts who have been on long-term missions in space and on bed rest subjects who have been exposed to reduced gravity environments on Earth. Here is an overview of the effects of space and microgravity on the human body.
Physical Effects - Weightlessness and reduced gravity environments cause a loss of bone and muscle mass, reduced blood flow, and changes in fluids in the body.
Additionally, the air inside the spacecraft or reduced gravity environments on Earth can cause an increase in allergens and bacteria, and an increase in CO2.
Psychological Effects - Exposure to space and microgravity can cause psychological changes such as anxiety, depression, and difficulty in making decisions.
These effects are more pronounced during long-term space travel and may pose a risk to crew members.

NASA astronaut Sunita Williams exercises on a treadmill aboard the ISS. (Image credit: NASA Ames)
Challenges of Long-Term Space Exploration
Humans have been, and will continue to be, exploring space. As we go further into space and on longer missions, the challenges will be how to protect the crew and how to keep them safe in this hostile environment. There are many issues to be considered.
One of them is the psychological effects of long-term space travel. Scientists are also trying to understand and prevent the physical effects of being in space, such as loss of bone and muscle mass and changes in fluids in the body. Another challenge is how to deal with the effects of radiation in space and how to keep the air inside the spacecraft clean and healthy for the crew.
Current Research
As scientists learn more about the effects of space and microgravity on the human body, they are looking for ways to reduce negative effects and to enhance positive effects. They are also developing technologies and techniques to ensure crew safety during long-term missions to other planets. Here is a list of some of the current research topics related to the effects of space and microgravity on the human body:
Bone and Muscle Loss - scientists are trying to understand how microgravity and weightlessness affect the bones and muscles. They also want to know if the bones and muscles can recover if they are subjected to a gravitational stimulus.
Cardiovascular Issues - researchers are studying cardiovascular changes related to the microgravity environment and how much is due to the environment and how much is due to the age of the crew members.
Immune System and Allergens - scientists are looking for ways to reduce the growth of allergens in the spacecraft and to enhance the immune system of the crew members so that they can combat these allergens.
Radiation - the radiation in space is a major concern for long-term space travel. Researchers are studying the effects of radiation on the crew members and are trying to find ways to protect against it.
Conclusion
Humans have been, and will continue to be, exploring space. As we go further into space and on longer missions, the challenges will be how to protect the crew and how to keep them safe in this hostile environment. There are many issues to be considered and besides the extensive research that has been done over the past few decades, there is still a lot that we do not know. There is much work to be done in the years to come.