Space environment: an unusual occupation with uncommon activities yields prolonged effects on the human body. Space expedition means long-term weightlessness which can have inauspicious effects on the human body, among them the significant are: loss of skeletal muscle mass and skeleton decay, deceleration of circulatory system, immune system alteration, balance disorganization, and eyesight disorders.
Moreover, the typical symptoms experienced are shortness of breath, rounded appearance of the face, loss of body weight, and sleep disorders.
What inner Functions of the human body get affected?
- Our Cardiovascular System encounters the same effects of microgravity as the whole human body experiences.
- As the cardiovascular system is vital for our proper functioning, the disturbances cause great challenges for people during their space operation.
- Prolonged heart exposure to deep space’s proton and ion radiation can result in coronary artery degeneration and aortic stiffness.
- Approximately, 10-15% of plasma gets reduced in blood.
- The headward fluid shifts occurring due to microgravity, cause such changes.
- To avoid complications caused by changes in the cardiovascular system, G-suits should be designed accordingly.
- During an expedition, a large mechanical load is subjected to the human skeleton during routine actions like walking and lifting.
- Long-durational flights lead to severe changes in calcium balance in bones.
- Chronic bone losses have been noticed in the lower body specifically pelvic bones, lumbar vertebrae, and femoral neck.
- Certain experimenters report bone elongations in rats after spaceflights.
- Some astronauts following a 6-month operation had losses of 10% in areal bone mineral density (aBMD) specifically detected in the hip and spine area.
- Many risk factors contribute to this bone loss e.g. reduced physical activity, a diet deficiency, and adaptation to weightlessness.
Decreased thin filament density of fibers:
- Study shows that the thick filaments remain unchanged during spaceflights but there is a significant decrease in the density of thin filament.
- Regulation of thin filament stability is made by cap-Z and tropomodulin actin capping proteins.
- The average stress in these filaments is 23-30% higher than normal.
- Spaceflight results in an increase in thick filament and not thin filament proteins in the paramyosin.
- Soleus fiber disorganization following a spaceflight show similar results as observed after 17 days of bed rest.
- Space flight mechanisms have multiple factors like sleep disruption, nutritional factors, stress, isolation, microbial contamination, and microgravity which alter certain functions of the immune system.
- These inconveniences, in turn, cause a weak defense against infections and tumors and they reactivate.
- Certain chemicals in the space environment repress immune responses.
- All environmental stressors found in space have a combined effect on the immune system of the human body.
- Infectious and foreign microorganisms present in the space environment, in turn, attack the already ailing immune system.
The countermeasures for short-duration flights have successfully been found but the long duration flights still cause obstacles for the astronauts. However, scientists and clinicians are struggling to find possible solutions as we might venture back to the moon or mars.