Spending a long time in space affects the human body in many ways, from weakening muscles and bones to changing eyesight and even gut bacteria. Some astronauts have stayed in space for over a year, giving scientists valuable insights into how weightlessness impacts the body. This research is important as humans plan for future missions, like traveling to Mars, which could take more than three years.
Muscles and Bones
In microgravity, astronauts’ muscles and bones don’t have to work as hard as they do on Earth. This leads to muscle loss, especially in the legs and back, and bone weakening. Astronauts can lose 1-2% of their bone mass each month, increasing their risk of fractures when they return. They exercise for about 2.5 hours daily to reduce these effects, but studies show that even this may not be enough.
Weight and Height Changes
Astronauts often lose weight in space, even though NASA provides nutritious meals. They can also grow slightly taller because their spines stretch without gravity pulling them down. However, this can lead to back pain and possible slipped disks when they return to Earth.
Eyesight Issues
Without gravity, fluids in the body shift, causing pressure in the head. This can lead to swelling in the eyes, making vision blurry. Some astronauts experience lasting changes in their eyesight. They also report seeing flashes of light due to cosmic rays hitting their eyes.
Gut Bacteria and Skin Sensitivity
Astronauts’ gut bacteria change due to different diets, radiation exposure, and less physical activity. Some also experience skin rashes and increased sensitivity when they return.
As humans prepare for deep space missions, scientists continue studying how to keep astronauts healthy for long periods. Finding better ways to maintain muscle, protect vision, and reduce radiation exposure will be key to future space exploration.
