COSMONAUT SERGEY KORSAKOV, 40, spent more than six months on the ISS in 2022. He says it was one of the most incredible experiences of his life, but is quick to warn of the effects of an extended stay in space on the body and mind.
“Physically, the microgravity environment leads to muscle atrophy and bone density loss (up to 1 per cent per month), as the lack of gravitational force reduces the need for the body to support itself,” he told THE WEEK. “Additionally, fluid shifts can cause facial puffiness and increased intracranial pressure, sometimes leading to vision problems. The radiation exposure in space is also higher, which increases the long-term risk of cancer.”
It is well-known that astronauts are required to exercise daily. Korsakov explains why that is so key. “Resistance and cardiovascular exercises are crucial to counteract the effects of microgravity,” he said. “I used to engage in regular exercise routines using specialised equipment to maintain muscle mass and bone density.” He also stressed the importance of nutrition. “A diet rich in calcium and vitamin D helped maintain bone health,” he said.
The effect on circadian rhythm is another concern. “There is lack of natural light cycles and the monotonous environment can disrupt circadian rhythm, potentially leading to sleep disorders,” he said, adding that ensuring sleep hygiene by managing light exposure and using sleep aides when necessary can help.
Korsakov adds that the isolation, confinement and distance from earth can contribute to stress, anxiety and loneliness. “The constant need for vigilance and the high stakes of the mission can contribute to mental fatigue and cognitive decline over time,” he said. Staying in regular contact with mission control and family helped Korsakov, besides engaging in hobbies and leisure activities. He also got psychological support via regular consultations.
Post-mission rehabilitation programmes, said Korsakov, were essential to recover from the physical de-conditioning experienced in space. “These typically include physiotherapy and gradual re-adaptation to earth’s gravity,” he said. “Psychological support continues after the mission to help cosmonauts reintegrate into life on earth and process their experiences.”
Another important step is monitoring and correcting vision alterations caused by the shifting fluid in the body putting pressure on the optic nerve. Fluid redistribution in microgravity can also affect cognitive function. Fluid levels normalise within a few days of returning to earth, typically, but astronauts may still require assessments and support.
Radiation exposure is another significant concern. Despite the protection offered by the ISS, astronauts are exposed to higher levels of cosmic radiation because of the lack of the shield that is the earth’s atmosphere. This can damage DNA and increase the risk of cancer. Long-term medical surveillance is necessary to monitor potential health issues arising from this exposure.
The brain being confused by the change in gravity leads to space sickness―nausea, vomiting and headaches. However, this condition does not last long. After a few days in space, the brain adapts and space sickness usually goes away. Sometimes, being back on earth can cause a similar condition called gravity sickness. Another condition that goes away as the body adjusts in space is swelling in the mucous membranes of the nose, leading to stuffy noses.
After returning to earth, astronauts may also feel dizzy when they stand up―a result of a form of low blood pressure. This happens because of the earth’s gravity making it harder for the heart to pump blood up to the head, compared with space.
It is expected that Sunita Williams and Barry Wilmore will return early next year. They will undoubtedly be put on a comprehensive health and wellness programme to tackle these multifaceted challenges. The duo’s experience underscores the importance of ongoing research and development on countermeasures to ensure the well-being of astronauts during and after their missions. As we continue to push the boundaries of space exploration, understanding and mitigating these effects will be crucial for the success of future long-duration missions.