Weight loss in mildly to moderately obese patients with obstructive sleep apnea.

The therapeutic effects of weight loss were evaluated in 15 hypersomnolent patients with moderately severe obstructive sleep apnea. As patients decreased their body weight from 106.2 +/- 7.3 kg (mean +/- SE) to 96.6 +/- 5.9 kg, apnea frequency fell from 55.0 +/- 7.5 to 29.2 +/- 7.1 episodes/h (p less than 0.01) in non-rapid-eye-movement sleep with an associated significant decline in the mean oxyhemoglobin saturation during the remaining episodes of sleep apnea from 11.9 +/- 2.4% to 7.9 +/- 1.9% (p less than 0.02). Sleep patterns also improved, with a reduction in stage I sleep from 40.2 +/- 7.3% to 23.5 +/- 4.8% (p less than 0.01), and a rise in stage II sleep from 37.3 +/- 7.0% to 49.4 +/- 4.6% (p less than 0.03). In the 9 patients with the most marked fall in apnea frequency, the tendency toward daytime hypersomnolence was decreased (p less than 0.05). No significant changes in sleep patterns occurred in 8 age- and weight-matched control patients who did not lose weight. Moderate weight loss alone can alleviate sleep apnea, improve sleep architecture, and decrease daytime hypersomnolence.