Space travel destroys 3 million red blood cells per second

The next “giant leap” for humans may be a trip to Mars,but having enough oxygen-carrying red blood cells for the journey might present a challenge,new research suggests.

Even space tourists lining up for short trips might have to stay at home if they are at risk for anaemia,or red blood cell deficiency,researchers said.

A man dressed as an astronaut steps off a train in Istanbul,Turkey,as part of a campaign to promote a NASA Space Exhibition in December.

A man dressed as an astronaut steps off a train in Istanbul,Turkey,as part of a campaign to promote a NASA Space Exhibition in December.AP

Astronauts are known to experience “space anaemia” but,until now,it was thought to be temporary. One NASA study called it “a 15-day ailment”.

But in fact,anaemia is “a primary effect of going to space,” said Dr Guy Trudel of the University of Ottawa,who led a study of 14 astronauts funded by the Canadian Space Agency.

Doctors attributed it to destruction of red blood cells,or hemolysis,resulting from fluid shifts as astronauts’ bodies accommodated to weightlessness and again as they re-accommodated to gravity.

“As long as you are in space,you are destroying more blood cells than you are making,” Trudel said.

Jeff Bezos’ Blue Origin’s New Shepard rocket launches carrying passengers William Shatner,Chris Boshuizen,Audrey Powers and Glen de Vries from its spaceport near Van Horn,Texas.

Jeff Bezos’ Blue Origin’s New Shepard rocket launches carrying passengers William Shatner,Chris Boshuizen,Audrey Powers and Glen de Vries from its spaceport near Van Horn,Texas.AP

Normally,the body destroys and replaces nearly 2 million red blood cells per second. Trudel’s team found astronauts’ bodies destroyed 3 million red blood cells per second during their six-month missions.

“We thought we knew about space anaemia,and we did not,” Trudel said.

The astronauts generated extra red cells to compensate for the destroyed ones. But,Trudel asked,how long can the body constantly produce 50 per cent more red cells? A round trip mission to Mars would take about two years,NASA estimated.

“If you are on your way to Mars and ... you can’t keep up” with the need to produce all those extra red blood cells,“you could be in serious trouble,” Trudel said.

Having fewer red blood cells in space is not a problem when your body is weightless,he added. But after landing on Earth,and potentially on other planets,anaemia could affect astronauts’ energy,endurance and strength.

A year after returning to Earth,the astronauts’ red blood cells had not completely returned to pre-flight levels,his team reported on Friday in Nature Medicine.

Trudel also studies the effects of immobility on patients who are bedridden for weeks or months.

The new findings mimic what he sees in his patients,he said,which suggested that what happens in space may also be happening in immobile patients.

“A solution to one could also apply to the other,” he said.

Sulekha Anand,who researches human physiology at San Jose State University and was not involved in the study,agreed.

“The findings have implications for understanding the physiological consequences of space flight and anaemia in patients on the ground,” she said.

Trudel was team is studying ways to solve the problem,he said.

Reuters

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