Over the past 60 years, about 600 people have been to space. Most of them were middle-aged men, and their missions lasted less than 20 days. Private companies now offer short-term flights into orbit, which can last from a few hours to several days. But future flights of professional astronauts into space will be longer. At the same time, more ordinary people will be sent beyond Earth as space tourists. So scientists continue to study how the human body reacts to the extreme conditions of space. A new scientific paper published in the journal Nature offers a new look at the health of people who go into space, writes The Conversation.
Back in 2019, the authors of this study published a groundbreaking scientific paper on how a year aboard the International Space Station (ISS) affects the human body. The hero of the study was NASA astronaut Scott Kelly.
Scientists studied Scott’s blood samples taken before, during, and after his return to Earth. They found that his telomeres, the protective caps on the ends of his chromosomes, had lengthened unexpectedly during his year in space. After returning home, his telomeres shortened rapidly. Over the next few months, his telomeres grew back, but were shorter than they had been before Scott went into space. Telomeres are known to shorten with age, including due to stress. Their length can also indicate the risk of dementia, cardiovascular disease, and cancer.
In a new study, scientists looked at 10 astronauts who spent six months on the ISS. These people’s telomeres also grew longer, and then shrank after returning to Earth. But there were more short telomeres than before.
After that, the scientists conducted a study with mountain climbers. It turned out that when climbing Mount Everest, the climbers’ telomeres became longer, and after the descent they became shorter again. The results show that it was not the microgravity of the ISS that led to changes in telomere length, but other reasons, such as increased radiation exposure.
The new study also looked at the telomeres of the crew of SpaceX’s 2021 Inspiration4 mission, which consisted entirely of non-professional astronauts. All of the crew members’ telomeres lengthened during the mission, and three of them shortened after landing.
But this mission lasted only three days. This means that even short space flights can have a significant impact on the human body. It is not entirely clear how exactly changing the length of telomeres affects human health, and more research is needed, scientists say.
Preliminary results also suggest that telomeres are damaged during spaceflight due to exposure to cosmic radiation.
Most interestingly, the study found that plants that had been in space did not have longer telomeres because they produced a special enzyme that maintained the length of the protective caps on chromosomes. This finding suggests that plants may be better equipped to withstand the stresses of space than humans.
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2024-07-04 10:30:42