Three Johns Hopkins University studies found that three conditions linked to obesity are also associated with such sleep-disordered breathing conditions as sleep apnea.
According to reports published in the February issue of the American Journal of Respiratory and Critical Care Medicine, insulin resistance, liver disease and an inactive lifestyle were all found to be linked with breathing abnormalities that many people suffer while sleeping, regardless of the individual's weight.
One study found a strong tie between the body's inability to metabolize glucose and sleep-disordered breathing (SDB), pauses or other abnormalities in breathing while sleeping. "What our research tells us is that SDB is characterized by multiple physiological deficits that increase the predisposition for type 2 diabetes mellitus," Study Leader Dr. Naresh Punjabi, an Associate Professor of Medicine and Epidemiology at Johns Hopkins University School of Medicine, notes.
A second study found that the lack of oxygen that occurs during obstructive sleep apnea (OSA) contributed to liver issues. Those liver problems increased proportionally with the severity of the breathing abnormality. "Our data suggest that patients with OSA and severe nocturnal hypoxemia should be screened for liver disease, and, conversely, patients with liver disease should be screened for OSA," Lead Researcher Dr. Vsevolod Y. Polotsky, of the Johns Hopkins Asthma and Allergy Center, says.
In a third study, it was determined that physical inactivity, such as sitting or standing for long periods of time, can cause fluid retained in the legs during the day to become redistributed to the upper body while sleeping. Why is this an important finding? Dr. T. Douglas Bradley, Professor of Medicine and Director of the Centre for Sleep Medicine and Circadian Biology, University of Toronto, explains: "An important implication of our observations is that sedentary living may predispose to OSA, not only by promoting obesity but also by causing dependent fluid accumulation in the legs, which can shift rostrally to the neck overnight. Therefore, it is plausible that if some of the displaced fluid reached the neck, it may predispose one to upper airway constriction."
These discoveries may help explain why 40 percent of people with sleep apnea are not overweight and why exercising may help reduce sleep-disordered breathing, even when there is no weight loss. News Release: Problems tied to obesity also seem to affect sleep January 23, 2009 www.news.yahoo.com 
