A study in the February issue of the Journal of Clinical Sleep Medicine suggests that intra-individual variability in obstructive sleep apnea severity may be partly explained by day-to-day changes in evening leg fluid volume and overnight rostral fluid shift from the legs to the neck. According to the authors, this fluid shift may narrow the pharynx and contribute to OSA.

Read nbsp;Night-to-night Variability in Obstructive Sleep Apnea Severity: Relationship to Overnight Rostral Fluid Shift in JCSM