Study Uncovers Microgravity’s Effects on Age-Related Muscle Loss
Researchers are exploring the impact of microgravity on age-related muscle decline, particularly in older adults. A recent study published in Stem Cell Reports investigates how spaceflight contributes to sarcopenia, a condition characterized by loss of muscle mass and strength in the elderly. This study aims to provide insights into the long-term health effects of microgravity on muscle function, which could benefit astronauts during extended missions and inform strategies to address muscle decline on Earth.
To conduct their research, scientists launched skeletal muscle microtissues from both young and older adult donors aboard the SpaceX CRS-25 mission to the International Space Station (ISS) between July and August 2022. The primary goal was to understand the mechanisms of muscle atrophy in microgravity and to test whether electrical stimulation could counteract these effects. Previous studies indicate that astronauts can lose about 30 percent of their skeletal muscle mass after just one month in space, highlighting the urgency of this research.
The findings revealed that microgravity alters the expression of 86 muscle-specific age-associated genes. Notably, younger muscle fibers demonstrated a more favorable response to electrical stimulation compared to those from older donors. This discovery offers a hopeful approach to mitigate muscle loss during space missions. Dr. Siobhan Malany, an associate professor at the University of Florida and co-author of the study, stated, “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.”
The phenomenon of muscle loss in space has been well-documented since the early days of human spaceflight. Astronauts typically lose around 20 percent of their muscle mass during missions lasting only 5 to 11 days. Longer missions have been associated with losses of up to 30 percent. This atrophy is primarily attributed to the absence of gravitational force, which reduces the need for lower back and leg muscles as astronauts do not perform weight-bearing activities.
To combat muscle loss, astronauts aboard the ISS engage in a rigorous daily exercise regimen that includes two hours of workouts on specialized equipment designed to simulate weightlifting. Recent studies, such as one published in Ageing Research Reviews in 2023, have indicated that spaceflight accelerates aging processes in muscles, while another study in Scientific Reports in 2024 examined how spaceflight alters biological markers associated with muscle health.
A notable case study involves the year-long mission of NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko, who lived on the ISS from March 2015 to March 2016. Upon their return to Earth, both astronauts experienced significant loss of bone and muscle mass, underscoring the need for comprehensive understanding of the physiological impacts of prolonged spaceflight.
As nations like the United States and China prepare to send astronauts to the Moon and eventually Mars in the coming years, the implications of this research are increasingly relevant. While lunar and Martian environments will not replicate full microgravity—these bodies exhibit one-sixth and one-third of Earth’s gravity, respectively—techniques such as electrical stimulation could play a crucial role in maintaining astronaut health during long-duration missions.
The ongoing research into the relationship between spaceflight and sarcopenia raises intriguing questions about future connections and discoveries in this field. As scientists continue to investigate, the importance of understanding muscle health in both space and on Earth becomes ever clearer.
