The Complex Relationship Between Weight and Sleep Apnea

Sleep apnea is an increasingly common disorder affecting up to 25 million Americans. Obstructive sleep apnea, the most common type, is caused by a narrow or blocked upper airway, resulting in disrupted breathing. These breathing interruptions result in the symptomatic snoring and gasping for air often associated with this sleep condition. While there are several risk factors for developing sleep apnea, being overweight or obese is the most important, according to the Mayo Clinic. The relationship between excess weight and sleep apnea is both reciprocal and complex. Research from the American Heart Association reveals that while not everyone who is obese will develop sleep apnea, about 60-90% of OSA patients are obese. And for OSA patients who were not overweight when first diagnosed, the daytime drowsiness and overall fatigue associated with this condition can lead to weight gain.

While insufficient sleep can cause internal physiological changes in the body, the risk of developing sleep apnea also increases due to the physical results of excessive body weight. Obese people carry extra weight in their necks, known as pharyngeal fat. These fatty deposits can block the airway during sleep, creating a perfect scenario for developing sleep apnea. In addition, increased abdominal fat puts pressure on the chest wall, which decreases lung capacity. It also results in reduced airflow and the risk of airway collapse. And it doesn’t take much excess weight to have this effect. According to the Journal of the American Medical Association (JAMA), a 10% increase in body weight can increase the risk of developing sleep apnea six-fold. 

There are also hormonal changes that occur with insufficient sleep, according to Healthline. New studies from the Sleep Foundation confirm that lack of sleep results in increased levels of ghrelin, known as the hunger hormone. Along with this hormonal increase comes a decrease in leptin, the fullness hormone. These hormonal changes result in overeating, consuming more calories, and weight gain. Additionally, the fragmented sleep associated with sleep apnea creates daytime fatigue and overall exhaustion, which make it more difficult to be physically active. When you combine all of these factors, it is easy to see how sleep apnea can cause weight gain. Obstructive sleep apnea is also associated with serious health co-morbidities, including cardiovascular disease, hypertension, and diabetes. Obesity elevates the risk of developing these same diseases, creating a dangerous mix of critical health conditions.

While the risk of sleep apnea in overweight people is well documented, new research shows that the reverse is also true. The body goes through various changes when it is deprived of sleep, making weight gain possible in OSA sufferers who are not overweight or obese. When there is less oxygen intake, as during a sleep apnea episode, there are changes to the body’s metabolism, which is the rate your body burns the calories you consume. Without increased activity and a reduction in caloric intake, the potential for weight gain is real. Coupled with the fatigue that accompanies sleep apnea, there is a slowdown in energy and activity levels, which can lower your metabolic rate, meaning that you can gain weight without consuming any additional calories. 

For those who suffer from OSA, getting back to a healthy body weight is a significant first step, although weight loss alone is not a cure for sleep apnea. Research has found that a 10-15% reduction in body weight can reduce the severity of OSA by up to 50%. Weight loss helps reduce the pharyngeal fat in the neck, allowing for less obstructed airways. Reducing abdominal fat helps decrease the compression on the chest wall, facilitating better airflow and less risk of collapsed airways. Weight loss also lessens symptoms of OSA. Daytime sleepiness and overall fatigue are reduced with weight loss, providing the energy needed for physical activity. Achieving a healthy body weight also helps to decrease the risk of co-morbid health conditions such as high blood pressure, type 2 diabetes, and cardiovascular disease. While weight loss can improve quality of life, additional therapies may be needed to control obstructive sleep apnea fully.

Being overweight and having sleep apnea are two separate but related health concerns sharing a complex relationship. If you have sleep apnea symptoms, it is best to discuss them with your healthcare practitioner. As sleep health is more widely researched, it is now clear that sleep is considered a pillar of good health, on equal footing with exercise and a healthy diet.