Rhodes Scholar still flying high
Commercial flying has become a routine mode of travel for millions of people around the world — but have you ever wondered what happens to your physiological make-up when you board that flight?
Aerospace medical specialist and Oxford-based researcher Dr Tom Smith has devoted his career to that very question.
The 2000 medical graduate, 2003 Rhodes Scholar and NASA-trained clinician-scientist has scaled some lofty heights over the past 12 years, researching the impact of low oxygen levels at high altitudes on the heart and lungs.
His field research has taken him to the Peruvian Andes for experiments with residents living in the world's highest town, Cerro de Pasco situated at 4340 metres above sea level, and comparing their heart and lung physiology with sea-level dwellers from Lima.
Many of Cerro de Pasco's residents live with chronic mountain sickness because of their failure to adjust to low oxygen levels. They develop problems such as excessive production of red blood cells (polycythaemia) and excessive lung blood pressure (pulmonary hypertension), resulting in a shorter life span.
The Peruvian study confirmed earlier laboratory tests which revealed the important role of iron in maintaining healthy lungs by moderating blood pressure increases when oxygen levels are low.
"If iron levels are low, this can increase the risk on individuals at high altitudes," Tom said.
"Volunteers from the mountain community whose iron levels were reduced via blood donations experienced a significant increase in blood pressure in their lungs.
"The healthy volunteers from Lima, however, who received intravenous iron had the opposite effect. The iron reversed much of the increase in lung blood pressure that was caused by the low oxygen."
Clinical trials are now under way to determine whether patients with certain lung diseases can benefit from treatment with iron.
In another study, Tom is currently investigating whether a similar link exists between Vitamin C levels and lung physiology. Study participants in London are being infused with ascorbate while enclosed in a large altitude chamber to test body responses to low oxygen.
When it comes to air travel, the good news is that the risks appear to be relatively low for healthy people.
"Oxygen is only mildly reduced during commercial airline flights," Tom said. "However, for medically-susceptible passengers with certain lung diseases, airline travel can be potentially dangerous."
Tom graduated with an MBBS from the University of Adelaide in 2000. In 2002, he won a Churchill Fellowship to study aerospace medicine at NASA's Kennedy Space Centre in the United States. He completed his PhD at the University of Oxford where he is now based, working as an academic clinical lecturer and researcher.
story by Candy Gibson
Dr Thomas Smith
Photo by Barnabas Smith