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Researchers are studying elite free divers to understand the limits of human physiology.
The insights could lead to better treatments for lung disease.
The world's top free divers can hold their breath for minutes at a time, embarking on extended underwater adventures without the aid of scuba equipment.
People with chronic obstructive pulmonary disease often struggle to get enough oxygen. In response, arterioles—tiny branches of the arteries—bringing blood to the lungs constrict. That leads to high pulmonary blood pressure and strains the heart.
"It's mostly thought of as a beneficial adaptation; if you inhale something blocking an airway, blood vessels going to that area will constrict and send blood elsewhere where it can pick up oxygen," says Andy Lovering of the University of Oregon. "But the problem is that if you deplete the oxygen from the entire lung, the pressure inside increases, causing pulmonary hypertension."...