How Space Affects the Human Body

Spending time in space can affect the human body and cause changes that may be somewhat unexpected. To most people, it is an unfamiliar environment and no matter how much is invested into preparation beforehand, some changes and ways in which the body reacts to them cannot be anticipated. NASA and other space agencies continue to explore and research these changes in order to ensure astronaut health and safety. So, what types of changes are typically seen in people who spend long periods of time in space? Let’s take a look at a few!

Physiological Effects of Space on the Human Body

Credit: Harvard University, Science in the News

Loss of Muscle Mass and Bone Density

While on Earth, humans develop bones and muscles in order to support their body mass/weight while under the influence of the Earth’s gravitation field. However, when astronauts make it into space, this support is no longer needed as they are in a microgravity environment. Without the constant pull of the Earth’s gravity, humans thus experience bone and muscle loss. In order to prevent this change from deteriorating the safety and well being of their astronauts, NASA typically works with them to assign a very nutritious diet and two hours of daily exercise.

Cardiovascular System, Brain, Eyes, and More

When entering an extended microgravity mission, another change that happens to the human body is an ”upwards” shift in blood and other bodily fluids. Outside of the Earth’s gravitational field, these fluids tend to move more towards the heart and the brain, causing several different changes and leading to increased risks. These risks include increased brain pressure, increased potential for hearing loss, deformation of the eye, changes in the shape of the heart, light headedness, nasal congestion, loss of ability to control blood flow, and much more. In fact, one study found that long-duration space flight can increase stroke volume by up to 35% and cardiac output by up to 41%.
Because space flight can impact the astronauts’ bodies in such significant ways, a lot has been done to develop methods and routines to decrease some of these risks. For instance, regular exercise (and specifically resistive exercise) can help maintain cardiovascular fitness. Astronauts can also wear special types of clothing to combat the effect of micro gravity. This includes trousers which use pressure differences to slow and prevent blood and other fluids from moving upwards.

Mental Health

Spending long periods of time in space can not only affect one’s physical health and well-being, but it has also proven to be a challenge for the astronauts’ mental health. To no one’s surprise, spending long periods of time on a space mission and therefore an isolated and confined environment typically negatively affects mental health. In fact, NASA’s research has revealed that the smaller the space and the less contact with people outside the mission, the more likely the astronauts are to develop some type of behavioral, cognitive, or psychiatric conditions. To combat this, NASA has invested a lot into researching ways to reduce these problems and boost astronauts’ morale through ways such as journaling, using virtual reality, or even creating a space garden.
 

Though this post highlights only a few, the list of ways in which space affects the human body is a lengthy one. Spending long periods of time in an environment typically unfamiliar to most humans is a natural stressor and can therefore impact the body in unexpected ways. That is exactly why NASA continues to invest into finding ways to best help our astronauts adapt to life in space and ultimately insure that they can return to Earth safe and healthy.