Effect of supine knee position on obstructive sleep apnea.

We previously reported a case of a middle-aged man whose obstructive sleep apnea (OSA) was virtually eliminated when he slept in the supine "knees up" position. In this study, we attempt to replicate this phenomenon in a group of volunteers with previously diagnosed OSA. Results indicated no significant improvement in OSA when sleeping supine knees up. Examination of distribution of within subjects' change [calculated as Respiratory Disturbance Index (RDI) in the "knees down" position vs RDI in the knees up position] indicated a trend for improvement in the latter (p=0.12, two-tailed probability). These results suggest that knee position is unlikely to be a robust intervention for OSA though they allow for the possibility that some patients may have a moderation of their condition by such a manipulation.

Age changes in timing and 24-hour distribution of self-reported sleep.

OBJECTIVE: Aging has been associated with increased nocturnal awakenings, increased napping, earlier bedtimes and wake-up times, and more regular sleep-wake schedules. These patterns have often been ascribed to both psychosocial and medical factors, but nearly all studies to-date have been cross-sectional. METHODS: The authors present self-reported sleep data from 31 elderly subjects followed over a decade. RESULTS: With aging, the number of nightly awakenings and daytime napping increased over time. Exploratory analyses suggested that individuals who lived with another person had earlier bedtimes, later wake-up times, and greater daytime napping. Intervening medical comorbidities also appeared to be associated with increased napping. CONCLUSION: These results confirm previous cross-sectional studies and suggest a complex biopsychosocial matrix for the timing and placement of sleep in elderly persons within the 24-hour day.