A study, published on October 15, 2009 in the American Journal of Respiratory and Critical Care Medicine, stated that being overweight increased an individual’s chances of oxygen desaturation in the blood.Oxygen desaturation, also known as hypoxia, is a pathological condition in which the body as a whole (generalized hypoxia) or a region of the body (tissue hypoxia) is deprived of adequate oxygen supply.
Paul E. Peppard, Ph.D. is the assistant professor of population health sciences at the University of Wisconsin-Madison and stated that it has been known that being overweight could have an effect on breathing, so the study was used to measure the relationship between how the degree of excess body weight relates to the severity of the apnea or hypopnea experienced by the test subjects.
Forty percent of the subjects in the overnight study were overweight and in these individuals there were over 37,000 instances of breathing issues. The researchers had found that sleep position, gender, age, and sleep phase (REM or non-REM) were associated with these breathing events, but noticed that an individual’s Body Mass Index (BMI) was an incredible contributor to how much the body’s tissues were starved of oxygen during the breathing events. It was found that each 10 point increase in a person’s BMI accounted for a 10% increase in how much the tissues were deprived of oxygen.
Dr. Peppard stated in the study that anyone with a BMI over 25 seems to have an increase in the risk and severity of apneas and hypopneas. In regards to the sleep phase, the greatest desaturation occurred during REM sleep rather than non-REM sleep.
Also collaborating in the study was Mary Morrell Ph.D. from the Imperial College London and she stated that out of all of the factors that influence oxygen desaturation, being overweight is one of the factors that can be modified. The only other modifiable factor in the study was sleep position. In other cases, those who smoked experienced an increased risk of oxygen desaturation in the blood. Smoking is another modifiable factor in those who smoke.
The study revealed that there are additional health concerns when overweight. At this time, more research must be done to further understand the consequences of apnea and hypopnea, such as what repeated oxygen desaturation can do over time. However, the study opens a door that allows clinicians to better understand the consequences and risk factors associated with excess weight and sleep-disordered breathing.