Astronaut study reveals effects of space travel on human bones

By Will Dunham

WASHINGTON (Reuters) – A examine of bone loss in 17 astronauts who flew aboard the Worldwide Area Station is offering a fuller understanding of the consequences of house journey on the human physique and steps that may mitigate it, essential data forward of potential bold future missions.

The analysis amassed new knowledge on bone loss in astronauts attributable to the microgravity situations of house and the diploma to which bone mineral density could be regained on Earth. It concerned 14 male and three feminine astronauts, common age 47, whose missions ranged from 4 to seven months in house, with a median of about 5-1/2 months.

A 12 months after returning to Earth, the astronauts on common exhibited 2.1% diminished bone mineral density on the tibia – one of many bones of the decrease leg – and 1.3% diminished bone power. 9 didn’t recuperate bone mineral density after the house flight, experiencing everlasting loss.

“We all know that astronauts lose bone on long-duration spaceflight. What’s novel about this examine is that we adopted astronauts for one 12 months after their house journey to know if and the way bone recovers,” stated College of Calgary professor Leigh Gabel, an train scientist who was the lead writer of the analysis revealed this week within the journal Scientific Reviews https://www.nature.com/articles/s41598-022-13461-1.

“Astronauts skilled vital bone loss throughout six-month spaceflights – loss that we’d anticipate to see in older adults over 20 years on Earth, they usually solely recovered about half of that loss after one 12 months again on Earth,” Gabel stated.

The bone loss happens as a result of bones that sometimes can be weight-bearing on Earth don’t carry weight in house. Area businesses are going to want to enhance countermeasures – train regimes and diet – to assist forestall bone loss, Gabel stated.

“Throughout spaceflight, tremendous bone constructions skinny, and finally a number of the bone rods disconnect from each other. As soon as the astronaut comes again to Earth, the remaining bone connections can thicken and strengthen, however the ones that disconnected in house cannot be rebuilt, so the astronaut’s total bone construction completely adjustments,” Gabel stated.

The examine’s astronauts flew on the house station previously seven years. The examine didn’t give their nationalities however they had been from the U.S. house company NASA, Canadian Area Company, European Area Company and Japan Aerospace Exploration Company.

Area journey poses numerous challenges to the human physique – key considerations for house businesses as they plan new explorations. For example, NASA is aiming to ship astronauts again to the moon, a mission now deliberate for 2025 on the earliest. That might be a prelude to future astronaut missions to Mars or a longer-term presence on the lunar floor.

“Microgravity impacts a variety of physique techniques, muscle and bone being amongst them,” Gabel stated.

“The cardiovascular system additionally experiences many adjustments. With out gravity pulling blood in the direction of our toes, astronauts expertise a fluid shift that causes extra blood to pool within the higher physique. This will have an effect on the cardiovascular system and imaginative and prescient.

“Radiation can also be a big well being concern for astronauts because the additional they journey from Earth the better publicity to the solar’s radiation and elevated most cancers threat,” Gabel stated.

The examine confirmed that longer house missions resulted each in additional bone loss and a decrease probability of recovering bone afterward. In-flight train – resistance coaching on the house station – proved necessary for stopping muscle and bone loss. Astronauts who carried out extra deadlifts in comparison with what they normally did on Earth had been discovered to be extra prone to recuperate bone after the mission.

“There’s a lot we nonetheless have no idea concerning how microgravity impacts human well being, notably on house missions longer than six months, and on the long-term well being penalties,” Gabel stated. “We actually hope that bone loss finally plateaus on longer missions, that folks will cease dropping bone, however we do not know.”

(Reporting by Will Dunham, Enhancing by Rosalba O’Brien)