Space agencies are working to overcome several challenges astronauts face while in space, such as reliable communication and fuel management, and a new threat has just been added to the list – anemia.
A study conducted by researchers in Ottawa found astronauts’ bodies destroy 54 percent more red blood cells while in space than when on the ground.
On Earth, our bodies create and destroy 2 million red blood cells every second, but researchers found those in space for six months destroyed 3 million every second.
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.
A study conducted by researchers in Ottawa found astronauts’ bodies destroy 54 percent more red blood cells while in space than when on the ground
In fact, anemia 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. ‘As long as you are in space, you are destroying more blood cells’ than you are making.’
However, just as our bodies generate red blood cells to compensate those destroy while on Earth, astronauts’ bodies do the same.
But, Trudel asked, how long can the body constantly produce 50 percent more red cells?
A roundtrip 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.
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. Tim Peake had his blood drawn aboard the International Space Station for the study
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, anemia 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.
The new findings mimic what he sees in his patients, he said, which suggests 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.
On Earth, our bodies create and destroy 2 million red blood cells every second, but researchers found those in space for six months destroyed 3 million every second. Experts question how long can the body constantly produce 50 percent more red cell. Pictured is David Saint-Jacques having his blood drawn aboard the International Space Station
‘The findings have implications for understanding the physiological consequences of space flight and anemia in patients on the ground,’ she said.
A separate study from March 2021 revealed long spaceflights can shrink the heart, in what could be a worrying finding for the next generation of astronauts.
Even a long-term program of low-intensity exercise in space is not enough to counteract the effects of prolonged weightlessness on the heart, according to researchers at the University of Texas Southwestern Medical Center.
Both men lost mass in their left ventricle – one of the two large chambers at the bottom of the heart – over the duration of their campaigns, despite substantial amounts of exercise, the researchers found.
Microgravity in space means the heart doesn’t have to work as hard to pump blood around the body, causing atrophy – a reduction in tissue.
It presents a serious issue for astronauts during long-term space flight, as it decreases bone density, increases risk of bone fractures and degrades muscles.
Leader of the study Professor Benjamin D. Levine at University of Texas Southwestern Medical Center said in a statement: ‘The heart is remarkably plastic and especially responsive to gravity or its absence.
”Both the impact of gravity as well as the adaptive response to exercise play a role, and we were surprised that even extremely long periods of low-intensity exercise did not keep the heart muscle from shrinking.’
HOW DOES SPACE RADIATION IMPACT ASTRONAUTS’ HEALTH?
Astronauts journeying to Mars would likely be bombarded with 700 times the levels of radiation experienced on Earth.
Even on the International Space Station, astronauts are exposed to 200 times more radiation as a result of their work than would be experienced by an airline pilot or a radiology nurse.
As a result, NASA is constantly monitoring local space weather information.
If a burst of space radiation is detected, mission control in Houston, Texas, can instruct astronauts to abort space walks, move to more shielded areas of the orbiting laboratory and even adjust the station’s altitude to minimise any health impacts.
Solar flare activity can cause acute radiation exposure effects — such as changes to the blood, diarrhoea, nausea, and vomiting — which can be recovered from, and other impacts that are non-reversible and/or fatal.
Long-term cosmic ray bombardment is a greater concern.
This can increases the risks of cancer, generate cataracts and cause sterility.
It can also cause damage to the brain, central nervous system and heart, paving the way for various degenerative diseases.
DNA changes from space radiation can even be passed on to subsequent children.