Effects of Microgravity on Human Physiology

Microgravity, a condition where objects appear to be weightless, profoundly affects the human body. This environment is commonly experienced by astronauts in space, particularly on the International Space Station (ISS). Studying the body's response to microgravity is crucial for ensuring the health and safety of astronauts on long-duration space missions

Effects on Human Physiology

Heart and Blood Vessel

Microgravity affects the cardiovascular system in several ways. Body fluids shift towards the head, causing facial puffiness, nasal congestion, and potentially increased pressure in the skull, which can affect vision. The heart doesn't work as hard to pump blood, leading to a decrease in heart muscle mass and resulting in orthostatic intolerance, or difficulty standing upright, when astronauts return to Earth due to changes in blood pressure regulation.

Balance and Sensory

Many astronauts experience space motion sickness, including nausea, dizziness, and disorientation, especially during the first few days in space. The vestibular system, responsible for balance, is disrupted, affecting movement and coordination, which means astronauts need to adapt to these changes to perform tasks effectively in space.

Psychological and Behavioral

Living and working in a confined space like the ISS can lead to psychological challenges. Prolonged isolation from family and friends and living in a small space can cause stress and feelings of isolation. Maintaining mental health is crucial, often supported through communication with loved ones and recreational activities. Additionally, the lack of a natural day-night cycle can disrupt sleep patterns, which are managed with light therapy and structured schedules.

Musculoskeletal System

In microgravity, muscles and bones don't need to support the body's weight, leading to several changes. Muscles, especially in the legs and back, weaken and shrink from reduced use, so astronauts need to exercise regularly to maintain muscle mass and strength. Similarly, bones lose minerals and become less dense, a condition called spaceflight osteopenia, which is much more severe than osteoporosis on Earth.

Sources

- NASA Human Research Program (HRP)

- Article: "The Impact of Long-Duration Spaceflight on the Human Body: Key Physiological Changes"

- Article: "Physiological and Psychological Adaptations of Astronauts During Spaceflight"