Historically, spaceflight has been reserved for the very healthy. Astronauts are selected for their ability to meet the highest physical and psychological standards to prepare them for any unknown challenges. However, with the advent of commercial spaceflight, average people can now fly for enjoyment.

The aerospace medicine community has had very little information about what medical conditions or diseases should be considered particularly risky in the spaceflight environment, as most medical conditions have never been studied for risk in space - until now.

The aerospace medicine group at the University of Texas Medical Branch at Galveston recently studied how average people with common medical problems - high blood pressure, heart disease, diabetes, lung diseases like asthma or emphysema and back and neck injuries, surgeries or disorders - would be able to tolerate the stresses of commercial spaceflight.

Overall, they found that nearly everyone with well-controlled medical conditions who participated in this project tolerated simulated flight without problems. The study can be found in the journal Aviation, Space and Environmental Medicine.

"Physiological stresses of flight include increased acceleration forces, or 'G-forces,' during launch and re-entry, as well as the microgravity period," said lead author Dr. Rebecca Blue. "Our goal was to see how average people with common medical problems, who aren't necessarily as fit as a career astronaut, would be able to tolerate these stresses of an anticipated commercial spaceflight."

Some medical conditions are of particular interest within the commercial spaceflight industry, either because of the high rate of occurrence or because of the potential to cause sudden, serious medical events. The researchers studied how people with these common conditions performed when put through centrifuge simulations of spaceflight launch and re-entry.

The centrifuge allows researchers to mimic the acceleration of a rocket launch or of a spacecraft re-entering through the atmosphere. Astronauts regularly use centrifuges to train for their own spaceflights. The acceleration forces expected in a commercial spaceflight profile are tolerable, but can be uncomfortable, for healthy individuals.

The researchers wanted to see if they were equally tolerable for individuals with complex medical histories or whether there were certain conditions that would make it more difficult for them to handle the flight.

"This study further supports the belief that, despite significant chronic medical conditions, the dream of spaceflight is one that most people can achieve," said Blue.