Why humans become taller in space, Sunita Williams answers

economictimes.indiatimes.com:

Physical Changes in Space

In a previously aired interview, Williams shared intriguing insights about how the human body adapts to the space environment. She noted that astronauts experience several physical changes while in space. “Calluses on your feet disappear because you don’t walk, and your fingernails and hair grow faster,” Williams explained.

“Without gravity, some wrinkles on your face might temporarily smooth out due to fluid shifting upwards. Your spine also expands because there’s no pressure on the cartilage between your vertebrae, making you slightly taller in space.” However, she emphasized that these changes reverse upon returning to Earth. “You shrink back to your normal height, and your back might ache a bit as gravity reasserts itself,” she added.

Bone Density and Muscle Mass Concerns

Williams also highlighted the significant concern of bone density and muscle mass loss in space. “In microgravity, bones lose density quickly,” she said. To combat this, astronauts engage in rigorous exercise routines using specialized equipment. “We run on treadmills with harnesses to simulate gravity and lift weights to maintain muscle mass, particularly in the hips and legs. We also use exercise bikes for cardiovascular fitness,” she explained.

Radiation Exposure

Despite NASA's efforts to mitigate these effects, radiation remains a persistent challenge. Cosmic rays and other forms of radiation penetrate the spacecraft, exposing astronauts to levels far exceeding those experienced on Earth. This exposure