There is much that researchers understand about the physiology of the lung, but there is much that remains a mystery. Dr. Wagner and a team of researchers, including Robb W. Glenny, MD, a physiology professor at the University of Washington, have dispelled the principle that blood flow in the lung is governed by only gravity. Instead, the researchers have shown pulmonary circulation is not solely dependent on gravity. Dr. Wagner said the tree-like structure of the lung's arterial circulatory system is another major determinant of how blood flows in the lungs. The plane, a KC-135, gives its passengers the experience of weightlessness at zero gravity with intermittent plunges toward Earth that create two times the force of gravity.
Severe nausea is frequently the result.
During several of these flights on which Dr. Wagner was a passenger, the researchers studied the effect of weightlessness on the lung's circulation in a pig. Dr. Wagner and his team believe the study shows that gravity may account for only a minor portion of the blood flow in the lung and that the tree-like structure of the lung's circulatory system accounts for the remainder. This discordant finding remains a focus of Dr. Wagner's research.