- The fact that there is no gravity to hold you down is not liberating but creates numerous health problems in deep space.
- Astronauts can lose up to one-third of their muscle mass if they spend four or more months in space.
- Along with muscle atrophy, your bones change their mineral structure, which ultimately leads to bone loss.
If you are lucky, being in space might influence your mind, and you will probably experience the Earth overview effect, changing the way you look at our home forever. But what about your body? What happens when you spend time in deep space, and what kind of changes can you expect?
When you are in space, you expose your body and your mind to circumstances that can never be recreated entirely on Earth. To an extent, you can simulate changes in gravity, making it more or less stronger. Still, the levels of radiation and the feeling of isolation can never be replicated.
Muscle Atrophy And Microgravity
Once you are free of the gravity effects you experience on Earth, your muscles get weaker. If no force pulls you towards the ground while you walk, talk, sit, or stand, everything changes. The skeletal muscles are usually good when it comes to adapting to carrying different loads because of their feature known as plasticity.
If you spend some time in space, that load is almost nowhere to be found, because there is no gravity. This causes loss of muscle mass, known as muscle atrophy. Both women and men are similarly affected by this, and the research done on this suggests how astronauts can lose around 30% of their muscle mass if they are in space longer than 110 days. This is why all astronauts, or anyone that embarks into deep space exploration, must follow a tight exercise plan.
What About Your Heart?
The heart is, indeed, just another muscle in our body. An important one for sure, but still - just a muscle. The more time you spend in space, the weaker your heart gets. Because there is no gravity, our body needs less energy to move, and because of it - less blood circulates our system.
The lower limbs are usually the most affected because of this, as the heart is not strong enough to push the blood back up. Both blood pressure and heart rate are lowered once you are in space.
Aerobic Fitness Problems
If you combine muscle atrophy and a weak heart, this leads to a drop in a person's fitness. This means that aerobic activity, and potential, falls down in performance.
After only two weeks of spending time in space, research has shown that aerobic capabilities of astronauts were severely reduced. Up to 25% less oxygen enters the body when it reaches high levels of activity that stresses our metabolism.
Change In Bone Density
If muscles suffer, bones suffer as well. Astronauts literally lose about 3.5% of their bones after they are in space for longer than 16 weeks. Again, this is all because there is no gravity that can keep on the continuous load our bones go through on Earth.
In normal circumstances, the structure of the bones is regulated by two types of cells: osteoblasts and osteoclasts. Once you get in space, the balance that keeps a healthy bone structure changes. All of this leads to the reduction of bone mineral density, causing the loss of bone.
Immune System Degrades
Immunity, the complex defense system that protects us from anything that threatens our body, also fails in space.
Along with muscle atrophy and the constant diminishing of physical performance, the immune system has to deal with other factors. Stress and the realization of how isolated you are in space can create troubles for our immune system.