Actigraphic assessment of the circadian rest–activity rhythm in elderly patients hospitalized in an acute care unit

Hospitalization for acute illness is a major risk factor of rest–activity rhythm disturbance among elderly subjects. The rest–activity rhythm is disturbed by the acute illness, aging and hospital environment. The purpose of this study is to assess the rest–activity rhythm and light exposure (using a wrist worn actigraph) of 10 patients (mean age 81 years, seven females) admitted on an acute care unit, suffering from cardiac, respiratory or renal acute disease. A non‐parametric method was used to analyze activity data. With an improvement of the underlying diseases, the mean relative amplitude of rhythm increased from 0.31 ± 0.19 for the first 5‐day period after admission to 0.54 ± 0.21 for the second period before discharge (P