What happens to an astronaut's body while in space and after they arrive back on Earth?
After spending 286 days in space, astronauts Suni Williams and Butch Wilmore have returned safely to Earth.
Their SpaceX capsule landed off the coast of Florida on Tuesday evening, marking the end of their extended mission.
Following the landing, both astronauts were brought out on stretchers, a common practice to help them readjust to life on Earth.
"It's tough learning to live with gravity again," Wilmore said.
John Dewitt, a biochemist, explained the challenges astronauts face after long durations in space.
"Our bodies were really built to work in gravity," Dewitt said.
NASA's Countermeasures Lab has developed exercise routines to help astronauts maintain bone and muscle mass while in space.
"When you take that force away, you lose a really important stimulus that's crucial for health," Dewitt added.
Astronauts spend hours exercising daily to combat the effects of weightlessness.
Williams once demonstrated her training for a triathlon from space, competing against CNN's Dr. Sanjay Gupta, who was on Earth.
"You're going 17,500 miles," Gupta said.
"I'll be done like that," Williams replied, showcasing her confidence.
In space, body fluids shift from the legs to the upper body, which can lead to low blood pressure.
NASA has observed that long-duration flights can also impact brain structure, with fluid surrounding the brain expanding.
Scott Kelly, who spent 340 days aboard the International Space Station, noted the genetic effects of space on human health.
"When you get back, gravity starts pulling everything to your lower extremities," Wilmore said, describing the adjustment process.
Kelly experienced a temporary increase in height upon returning to Earth, but his body eventually returned to baseline after about six months.
Despite the challenges, Kelly found some unexpected benefits from his time in space.
"When I got back, I was told I had the softest feet," he said, reflecting on the unique experiences of astronauts.