A group of British scientists who trekked up Mount Everest has shed new light on how low levels of oxygen in the blood contribute to insulin resistance and adult-onset diabetes.
The researchers used the highest mountain in the world as a laboratory to observe changes in 24 healthy subjects as the levels of oxygen in their blood dropped, instead of studying people at sea level already suffering insulin resistance and Type 2 diabetes.
Insulin resistance, a precursor to full-blown diabetes, develops when cells in the body reject its own insulin, the hormone that regulates blood sugar. The pancreas then produces more insulin, and the resulting overload can cause damage to the heart, blood vessels, eyes, brain and other organs.
The researchers found that healthy people who spent eight weeks on Mount Everest started to develop the same signs of insulin resistance found in people who are overweight or obese.
"Fat tissue in obese people is believed to exist in a chronic state of mild hypoxia (low oxygen levels) because the small blood vessels are unable to supply sufficient oxygen to fat tissue," according to Mike Grocott, a professor at the University of Southampton, who co-founded of the Centre for Altitude, Space and Extreme environment medicine (CASE Medicine), which coordinated the research on Mount Everest. The Everest researchers, from the University of Southampton and University College London, reported their findings in the journal PLoS One.
At sea level, blood oxygen saturation typically hovers around 98 percent. By the time the study subjects reached base camp at 17,300 feet, their levels had dropped to around 82 percent.
The resulting inflammation and insulin resistance from low oxygen levels could point the way toward the development of treatments for other disorders that produce hypoxia, such as lung disease, stroke, and advanced age. Oxygen levels start to drop in everyone after the age of 40, and various disorders that reduce the ability of the blood to absorb adequate oxygen, such as sleep apnea and emphysema, aggravate the condition.
Tom Valeo writes on health matters. Email him at [email protected]