Your Body Mass Index -- the relationship between your height and weight -- can affect your health.
If you are overweight, defined by the World Health Organization as having a BMI of 25.0 or higher, you stand at increased risk of developing type 2 diabetes and cardiovascular disease. A high BMI can also increase your risk of hypoxia while, ironically, hypoxia may help you lose weight.
Causes of Hypoxia
Hypoxia means a lack of oxygen supply to your brain. This can be caused by external factors such as smoke inhalation, complications from general anesthesia, cardiac arrest, choking, drug overdose, high altitudes, strangulation, stroke and drowning. Hypoxia can be life-threatening because some brain cells die after five minutes of oxygen deprivation. Your BMI can also make you more prone to hypoxia because obesity is commonly linked to conditions such as sleep apnea, a condition in which breathing frequently stops during sleep.
Sleep Apnea
Obstructive sleep apnea -- OSA -- occurs when the throat muscles that support your soft palate, uvula, tongue and tonsils relax, narrowing or closing your airway. Elevated weight puts you at higher risk for OSA. Some people experience 30 or more breathing interruptions per hour of sleep, each interruption lasting 10 seconds or longer. OSA affects 24 percent of adult men and 9 percent of adult women, according to Daniel Gottlieb, director of the Sleep Disorders Center in Boston. Gottlieb says men with OSA face a 58 percent higher risk of developing heart failure than those without OSA.
Reducing Risk of Hypoxia
Losing weight could reduce your risk of hypoxia and other breathing disorders that may make you susceptible to high blood pressure, insulin resistance and systemic inflammation as well as cardiovascular disease, according to a study conducted by A. Romero-Corral and colleagues at the Mayo Clinic College of Medicine, Mayo Foundation for Medical Education and Research and published in the April 2010 issue of "Chest." On the other hand, a study conducted at Yale University did not find a sustained correlation between weight loss and improvement in sleep-related breathing disorders.
Hypoxia and Weight Loss
Although being obese affects your risk for hypoxia, subjecting yourself to moderate hypoxia could help you lose weight. Nikolaus Netzer and colleagues at Germany's Hermann Buhl Institute for Hypoxia and Sleep Medicine Research conducted an experiment in which overweight people were asked to exercise in simulated high altitude or normal altitude conditions. The researchers found that activity conducted at high altitudes helped people lose substantially more weight. The researchers speculated that metabolism was amped and appetite lowered in the high-altitude conditions, but that their study did not verify a direct cause. The success of Netzer's study does not mean you should embark on a high-altitude exercise program as risks may outweigh potential benefits. And you should consult your physician before beginning any workout regimen.
References
- The New York Times; Cerebral Hypoxia; (NO BYLINE) Dec. 26 2010
- Circulation: Journal of the American Heart Association; Obstructive sleep apnea linked with later risk of heart disease; Daniel J. Gottlieb etal; July 2010
- "Chest"; Interactions between obesity and obstructive sleep apnea: implications for treatment; A. Romero-Corral; April 2010
- "Clinic in Chest Medicine"; The Relationhip of Obesity and Obstructive Sleep Apnea; N. Shah etal; November 2009
- "Sleep Breath"; Low intense physical exercise in normobaric hypoxia leads to more weight loss in obese people than low intense physical exercise in normobaric sham hypoxia; Nikolaus C. Netzer, Roland Chytra and Thomas Kupper; May 2008
- World Health Organization: Body Mass Index
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