PurposeThe purpose of this study is to test the effects of a mild degree of head-of-bed elevation (HOBE) (7.5°) on obstructive sleep apnea (OSA) severity and sleep quality.MethodsOSA patients were recruited from a single sleep clinic (Criciúma, Santa Catarina, Brazil). Following a baseline polysomnography (PSG), all patients underwent a PSG with HOBE (within 2 weeks). In addition, a subset of patients performed a third PSG without HOBE.ResultsFifty-two patients were included in the study (age 53.2 ± 9.1 years; BMI 29.6 ± 4.8 kg/m2, neck circumference 38.9 ± 3.8 cm, and Epworth Sleepiness Scale 15 ± 7). Compared to baseline, HOBE significantly decreased the apnea-hypopnea index (AHI) from 15.7 [11.3–22.5] to 10.7 [6.6–16.5] events/h; p < 0.001 and increased minimum oxygen saturation from 83.5 [77.5–87] to 87 [81–90]%; p = 0.003. The sleep architecture at baseline and HOBE were similar. However, sleep efficiency increased slightly but significantly with HOBE (87.2 [76.7–90.7] vs 88.8 [81.6–93.3]; p = 0.005). The AHI obtained at the third PSG without HOBE (n = 7) returned to baseline values.ConclusionsMild HOBE significantly improves OSA severity without interfering in sleep architecture and therefore is a simple alternative treatment to ameliorate OSA.