Why does one critically ill patient survive while another does not? Equally, why can one climber summit Everest while his partner must turn around?

“The link may not appear obvious,” says Dr. Adam Sheperdigian, a research fellow at the UCL Centre of Altitude, Space, and Extreme Environment Medicine, “but both scenarios demonstrate a condition known as hypoxia, an inability to deliver enough oxygen to support the body’s vital organs.”

As a climber ascends to extreme altitude, he has less oxygen with each breath. During a slow, calculated ascent, his body negates this by increasing breathing rate and producing red blood cells. For some this acclimatization occurs without fail, while others develop critical and even fatal conditions.

Dr. Sheperdigian works with the Xtreme Everest Team, a specialist unit of medical providers and scientists using “the highest laboratory in the world,” Mount Everest, to learn more about hypoxia.

The team started work in 2007, studying more than 200 healthy volunteers in Everest Base Camp. The scientists also performed exercise tests at the 25,938-foot South Col and collected arterial blood samples just below the 29,029-foot summit. Returning in spring 013, Xtreme Everest will study a wider demographic, including children, identical twins and the indigenous Sherpa population.

Learn more at xtreme-everest.co.uk.