New research showcases cardiovascular effects of space travel

Human health is influenced by many factors: diet, exercise, family history, and — believe it or not — gravity. The Earth’s gravitational pull, or its absence, affects the movement of fluid throughout the body, impacting blood flow.

As space travel becomes more common, it’s crucial to understand the body’s reaction to changes in gravity and its effects on astronauts’ health. Using tilt tables, researchers from the Bioastronautics and Human Performance (BHP) Laboratory at Texas A&M University are investigating the effects of different gravity levels on the body, all without leaving campus.

"Gravitational forces have a profound impact on the cardiovascular and ocular systems, both in space and on Earth,” said Dr. Ana Diaz Artiles, an associate professor of aerospace engineering and director of the BHP. “By studying these effects under controlled conditions, we can better protect astronaut health during missions and translate these findings to clinical care for patients here on the ground.”

Dr. Adrien Robin, previous postdoctoral research fellow with BHP and current assistant professor in the Aerospace and Extreme Environment Nursing Program at Texas A&M, conducted this physiological study with funding from the Translational Research Institute for Space Health (TRISH). TRISH is a consortium led by Baylor College of Medicine, in collaboration with the California Institute of Technology in Pasadena, and the Massachusetts Institute of Technology in Cambridge.

Researchers are simulating spaceflight deconditioning using two different methods: 48 hours of six-degree head-down bedrest, or a drug-induced decrease in blood volume, known as hypovolemia. Hypovolemia plays a significant role in cardiovascular deconditioning in astronauts and can lead to adverse health effects when returning to Earth’s gravity.

Before and after deconditioning, researchers aim to understand how gravitational stress affects cardiovascular function by systematically adjusting body position on a tilting table and measuring key cardiovascular indicators, like pulse, blood pressure, or internal jugular vein flow. The findings will better characterize the body’s adaptation to gravity shifts, advancing clinical knowledge on Earth and improving health risk models for astronauts in space.

Preliminary results show that hypovolemia is clearly observed three hours after patients received a diuretic drug. This makes drug-induced hypovolemia a good model to mimic spaceflight deconditioning and study the fluid shift responses. The 48-hour bedrest portion of the study is still ongoing, and the results will be compared with the hypovolemic results. 

“Launching a clinical study with deconditioning intervention for the first time in our lab was a challenge,” Robin said. “We were able to coordinate with the Human Clinical Research Facility, Dr. Jason McKnight from the College of Medicine, and Dr. Lisa Haddad from the College of Nursing to safely conduct the drug-induced hypovolemia and bedrest interventions on healthy participants.”

Practical applications for this research include refining astronauts’ exercise routines, fluid intake protocols and compression garment usage during and after space missions. 

These findings also translate to clinical applications on Earth, such as optimizing patient positioning during surgery, designing rehabilitation plans for elderly or bedridden individuals, and managing fainting caused by sudden blood flow decreases to the brain — all situations where gravity plays a key physiological role.

“This project truly highlights the value of interdisciplinary collaboration,” Diaz Artiles said. “Engineers, physiologists, and medical professionals are working side by side to ensure participant safety and to push the boundaries of human health research in extreme environments.” 

Additional collaborators on the project include Dr. David Zawieja from the College of Medicine and Dr. Bonnie Dunbar from the Department of Aerospace Engineering, as well as BHP students Cort Reinarz, Huc Pentinat Llurba and Dave Laygo. 

Researchers plan to use the data from this study to test countermeasures against gravity-induced cardiovascular concerns, like compression garments or lower body negative pressure. Next steps also include performing a similar study in an environment with extreme temperature or humidity.

Funding for this research is administered by the Texas A&M Engineering Experiment Station (TEES), the official research agency for Texas A&M Engineering.