The study, led by neuroscience doctoral student Sushmita Arumugam Amogh and entomology assistant professor Ysabel Giraldo, used a custom-built centrifuge to expose common fruit flies to hypergravity levels ranging from 4G to 13G. The work fills a gap in understanding how extreme gravitational forces -- rather than the microgravity more commonly studied in space research -- affect biological systems.
"The centrifuge is like a merry-go-round," Arumugam Amogh said. "The faster you go, the more you feel pulled outward. That's hypergravity."
The team tracked movement using infrared sensors that recorded each time a fly crossed a beam inside a narrow tube. Researchers also tested climbing behavior, known as negative geotaxis, which is the natural tendency of flies to move upward against gravity.
Results varied with intensity. At 4G, flies exposed for 24 hours became markedly hyperactive. At 7G, 10G, and 13G, the pattern reversed: activity dropped and climbing decreased. In both cases, however, the animals recovered over time. Flies in the 4G group remained hyperactive for roughly seven weeks -- the majority of their lifespan -- before gradually returning to baseline. The 7G group also returned to normal activity levels, though their initial response had been suppression rather than elevation.
The researchers interpret the pattern as evidence that the brain actively adjusts energy allocation under gravitational stress. Moderate increases appear to drive greater movement, possibly as a metabolic response to higher physical demands. At more extreme levels, the cost of movement outweighs the benefit and the system shifts toward energy conservation.
"We believe what we're seeing is that gravity feeds directly into the brain's decision-making around energy use and movement," Arumugam Amogh said. "It helps determine whether to act or conserve energy."
Internal metabolic changes tracked alongside the behavioral data. Fat storage rose shortly after hypergravity exposure, then declined as activity increased, suggesting movement and metabolism are tightly coupled under stress.
The experiment was not confined to a single exposure window. Researchers tested three scenarios: 24 hours of hypergravity, continuous exposure across an approximately 50-day lifespan from egg to adult, and multigenerational exposure. In the final scenario, flies lived, mated, and reproduced for 10 consecutive generations entirely under elevated gravity. Long-term multigenerational studies of this kind have rarely been conducted, and the results add a broader dimension to understanding how organisms sustain function under prolonged physical stress.
The findings challenge a straightforward assumption about extreme environments -- that they primarily cause damage. Instead, the data describe a system that can be displaced far from its normal operating state and still recover.
With NASA's Artemis II mission having launched on April 1, 2026, and future crewed lunar missions planned under the Artemis program, the relevance of hypergravity research is increasing. Astronauts experience high-G forces during launch and atmospheric reentry. Insights into how organisms adapt to and recover from those forces could inform strategies to protect crew health on long-duration missions.
"I think our study is really timely," Giraldo said. "The link between gravity, physiology, and energy use will only become increasingly important to understand as space travel is poised to become more common in the future."
Research Report: Hypergravity exposure leads to persistent effects on geotaxis and activity in Drosophila melanogaster
Related Links
University of California, Riverside
Space Medicine Technology and Systems
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