Diet and Exercise Unlikely to Eliminate Sleep Apnea in Obese Patients

October 15, 2009

Continuous Positive Airway Pressure
A study has found that a diet and exercise program alone is unlikely to eliminate mild to moderate obstructive sleep apnea in obese patients.

Although the exercise program resulted in improved fitness and muscle strength, which is important in obese obstructive sleep apnea patients, diet and exercise alone should not be relied upon to treat obstructive sleep apnea, according to the researchers.

Obstructive sleep apnea is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. Obstructive sleep apnea occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway, which leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that last between 10 and 30 seconds. A common measurement of sleep apnea is the apnea-hypopnea index (AHI). This is an average that represents the combined number of apneas and hypopneas that occur per hour of sleep.

Results of the study showed improvement in typical obstructive sleep apnea symptoms including snoring, daytime sleepiness, impaired vigilance, poor quality of life and mood after the completion of a 16-week diet and exercise program. Weight loss was significant, with an average loss of 12.3 kg (about 27 pounds), representing 12.9 percent of baseline total body weight. Although weight loss reduced the average AHI by 25 percent from 24.6 to 18.3 breathing pauses per hour of sleep, the change was not statistically significant.

Twelve consecutive patients from the Institute for Breathing and Sleep who were newly diagnosed with obstructive sleep apnea were included in the cohort study, and 10 completed the program. Participants had mild to moderate obstructive sleep apnea, were obese with an average body mass index (BMI) of 36.1, were heavy snorers, had no significant co-morbidities and were able to exercise. Participants had an average age of 42 years, and nine of 12 were female.

An initial evaluation was performed to assess sleep disordered breathing, cardiovascular risk factors, and neurobehavioral function prior to and following completion of the 16-week program. The program used a proprietary low-energy diet and subjects participated in a hospital-based exercise schedule that included both aerobic and resistance training supervised by a physiologist and a physiotherapist. Subjects also completed questionnaires to assess subjective sleep quality, mood and quality of life.

A year after starting the program all but one participant who completed the program had regained some weight, but five of the 10 participants were able to independently maintain weight loss of at least seven percent. All participants said they had maintained an exercise program but that regular face-to-face contact would have assisted with ongoing adherence to a low-energy diet.

Although the American Academy of Sleep Medicine’s “Clinical Guideline for the Evaluation, Management and Long-term Care of Obstructive Sleep Apnea in Adults” recommends weight loss for all overweight obstructive sleep apnea patients, weight loss should be combined with a primary treatment for obstructive sleep apnea because of the low success rate of dietary programs and the low cure rate by dietary approach alone. The AASM recommends positive airway pressure (PAP) therapy as the treatment of choice for all severity levels of obstructive sleep apnea.
1. Maree Barnes, et al. A Diet and Exercise Program to Improve Clinical Outcomes in Patients with Obstructive Sleep Apnea- A feasibility Study. Journal of Clinical Sleep Medicine. Volume 05, Issue 05, Pages 409-415.

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