Aspects of the present disclosure include methods for determining the presence and/or concentration of an analyte. In practicing methods according to certain embodiments, an analyte sensing unit is positioned at a location on the abdomen of a that experiences involuntary movement sufficient to provide for mixing of non-circulating interstitial fluid with circulating interstitial fluid and determining an analyte concentration in the interstitial fluid. Also provided are methods for positioning an analyte sensing unit at a location on the abdomen of a subject, and methods of determining an analyte concentration while the subject is asleep, e.g., during a rapid eye movement (REM) sleep period. Devices and systems for practicing the subject methods also described.
