As the frequency of space travel increases, it’s crucial to understand the effects of altered gravity on the human body. Dr. Ana Diaz Artiles and her team at Texas A&M University are investigating the impact of space flight on eye health, particularly the consequences of gravitational changes.
During space travel, shifts in bodily fluids due to altered gravity can affect the cardiovascular system, potentially leading to changes in the vessels around the eyes.
As space travel becomes more accessible to individuals outside of traditional astronaut training, such as commercial space travelers, it’s essential to recognize the potential impact on cardiovascular and eye health, especially for those who may not have the same level of physical fitness as professional astronauts.
“When we experience microgravity conditions, we see changes in the cardiovascular system because gravity is not pulling down all these fluids as it typically does on Earth when we are in an upright position,” said Diaz Artiles, an assistant professor in the Department of Aerospace Engineering and a Williams Brothers Construction Company Faculty Fellow. “When we’re upright, a large part of our fluids are stored in our legs, but in microgravity, we get a redistribution of fluids into the upper body.”
The intriguing phenomenon of Spaceflight Associated Neuro-ocular Syndrome (SANS) has drawn significant attention due to its impact on astronauts’ eye health during space missions. Researchers, led by Diaz Artiles, are unraveling the underlying mechanisms of SANS in hopes of developing effective countermeasures.
A recent study explored the potential of lower body negative pressure (LBNP) as a promising intervention to mitigate the adverse effects of microgravity-induced fluid shifts. This research holds promise for ensuring astronauts’ ocular health and overall well-being during prolonged space missions.
While the exact role of ocular perfusion pressure (OPP) in the development of Spaceflight-associated Neuro-ocular Syndrome (SANS) is still uncertain, Diaz Artiles and her team have suggested that exposure to microgravity might result in a slight but persistent increase in OPP compared to upright postures, potentially contributing to the development of SANS.
However, their recently published study found that lower body negative pressure (LBNP), while successful in shifting fluid towards the lower body, did not effectively reduce OPP. If elevated OPP is indeed linked to SANS, it suggests that LBNP may not be an effective countermeasure for this syndrome. The team underscores the need for future research to better understand the relationship between OPP and SANS, as well as the impact of LBNP on these ocular responses, for the development of effective countermeasures.
“This research is just one experiment of a three-part study to better understand the effects of fluid shift in the body and its relationship to SANS. Previous experiments in this study included the use of a tilt table for researchers to understand the cardiovascular effects of fluid shifts at different altered gravity levels, recreated by using different tilt angles,” said Diaz Artiles.
The current study and ongoing research are dedicated to developing effective countermeasures for the fluid shift phenomenon, primarily focusing on lower body negative pressure. In the near future, the researchers plan to assess the effectiveness of using a centrifuge to address the fluid shift and its associated effects.
Diaz Artiles and her team are determined to gather comprehensive data on cardiovascular responses to each countermeasure and compare their impact on ocular perfusion pressure and other crucial cardiovascular functions affected by microgravity environments. As these studies are conducted on Earth, the researchers anticipate that gravitational variations in space may yield different results. As a result, they are eager to conduct future studies in true microgravity conditions, such as parabolic flights.
Journal reference:
- Eric A. Hall, Richard S. Whittle & Ana Diaz-Artiles. Ocular perfusion pressure is not reduced in response to lower body negative pressure. npj Microgravity, 2024; DOI: 10.1038/s41526-024-00404-5