Recent research published in Stem Cell Reports sheds light on how spaceflight affects sarcopenia, a condition characterized by age-related muscle decline, particularly in older adults. A team of scientists investigated the influence of microgravity on muscle cell function, with the findings potentially benefiting astronauts, mission planners, and the general public by enhancing understanding of the long-term health implications of prolonged exposure to microgravity.
To conduct this study, researchers launched skeletal muscle microtissues from both young and old adult donors aboard the SpaceX CRS-25 mission to the International Space Station (ISS) between July and August 2022. The primary objective was to assess how muscles atrophy during extended periods in microgravity and to determine the effectiveness of electrical stimulation in reversing this muscle loss.
Previous studies indicate that astronauts can lose approximately 30 percent of their skeletal muscle mass after just one month in microgravity. The current research identified that microgravity altered 86 muscle-specific age-associated genes. Notably, younger muscle fibers exhibited a more favorable response to electrical stimulation compared to older fibers, which provides promising avenues for mitigating muscle decline during space missions.
Dr. Siobhan Malany, an associate professor at the University of Florida and co-author of the study, emphasized the potential of this technology, stating, “Using electrical pulses to trigger real-time muscle contractions in space, we can simulate exercise and observe how it helps protect against rapid muscle weakening in microgravity. This technology advancement offers insight into how we might preserve muscle health during long-duration space missions and ultimately, how to combat age-related muscle loss here on Earth.”
The phenomenon of muscle loss in space is well-documented, with astronauts experiencing significant muscle atrophy due to the absence of gravitational forces. Research shows that astronauts can lose around 20 percent of their muscle mass during missions lasting only 5 to 11 days, while longer missions can result in greater losses. This atrophy primarily occurs because the lower back and leg muscles, which are essential for standing, are not utilized in a microgravity environment.
To counteract this issue, astronauts aboard the ISS engage in a rigorous exercise regimen, spending two hours daily using a treadmill, stationary bike, and specially designed equipment to simulate weightlifting on Earth. Recent studies, including one published in Ageing Research Reviews in 2023, further explore the connection between spaceflight and aging, while a 2024 study in Scientific Reports examines how spaceflight affects biological markers.
The importance of addressing muscle loss during space missions is underscored by the experiences of NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko, who undertook a year-long mission on the ISS from March 2015 to March 2016. Upon their return to Earth, both astronauts were found to have experienced significant bone and muscle loss, illustrating the need for further research into the physiological impacts of long-term spaceflight.
As nations like the United States and China prepare to send astronauts to the lunar surface in the coming years, and eventually to Mars, understanding the implications of microgravity on muscle health becomes increasingly critical. While future astronauts will not face complete microgravity on these planetary bodies—experiencing just one-sixth and one-third of Earth’s gravity, respectively—strategies like electrical stimulation could prove vital for maintaining astronaut health during extended missions.
The ongoing research into the relationship between spaceflight and sarcopenia promises to yield new insights in the coming years, raising awareness about the challenges astronauts face and the potential solutions that may emerge. As the scientific community continues to explore these connections, the imperative to enhance human health in space remains a priority.
