Spaceflight Research Examines Ageing Processes Similar to Those on Earth

Research on astronauts living aboard the International Space Station has identified several physiological changes that resemble accelerated ageing observed in some people on Earth. NASA astronaut Scott Kelly spent 340 days on the station as part of a study comparing him with his identical twin brother Mark, who remained on the ground.

Blood, urine and faeces samples collected before, during and after the mission showed elevated inflammatory markers, reduced anti-inflammatory molecules and signs of mitochondrial dysfunction in the space traveller.

Winer at the Buck Institute for Research on Aging identified four main contributors to these changes. They include the absence of gravity that reduces load on muscles and bones, a cycle of 16 sunrises and sunsets every 24 hours that disrupts circadian rhythms, exposure to ionising radiation equivalent to 480 chest X-rays over six months, and social isolation.

Subsequent studies of other astronauts have documented additional effects such as genomic instability, shifts in gut microbiome composition, endocrine disturbances and reduced nutrient sensing. Cardiovascular measurements have shown arterial stiffness increases that correspond to roughly 20 years of ageing within six months.

Winer and colleagues noted that sedentary lifestyles produce similar muscle and bone effects to microgravity. Circadian disruption and social isolation occur frequently on Earth, and some populations receive high radon exposure comparable to space radiation levels.

The researchers described spaceflight conditions as acute, intensified versions of the chronic stressors that contribute to age-related decline in terrestrial populations. NASA has collaborated with the Buck Institute team to identify molecules that might counteract these effects.

Past space programme research has produced medical applications including cochlear implants and artificial limbs. Work on ageing countermeasures could add to that list of spin-offs.