Relationships Among Physical Activity, Daylight Exposure, and Rest-Activity Circadian Rhythm in Patients With Esophageal and Gastric Cancer: An Exploratory Study.

Background: Although rest-activity circadian rhythm (RACR) disruption is associated with mortality in patients with cancer, few studies have examined the effect of RACR on patients with esophageal and gastric cancer.
Objective: The aim of this study was to identify the predictors of RACR.
Methods: This cross-sectional, single-site study included 276 patients with esophageal and gastric cancer recruited from chest-surgery and general-surgery outpatient departments. Actigraphy was used to assess objective physical activity (PA), daylight exposure, and RACR, and 3-day PA was used to indicate the subjective amount of PA. The parameter of objective PA was the up activity mean; the parameter of daylight exposure was >500 lx, and the parameters of RACR were the 24-hour correlation coefficient, in-bed less than out-of-bed dichotomy index, midline estimating statistic of rhythm, and amplitude. The subjective amount of PA was calculated as the sum of mild, moderate, and vigorous PA.
Results: The up activity mean predicted 24-hour correlation coefficient. The PA amount and up activity mean predicted in-bed less than out-of-bed dichotomy index. The up activity mean and >500-lx daylight exposure predicted midline estimating statistic of rhythm. Finally, the PA amount and up activity mean predicted the amplitude.
Conclusions: Increased PA and daylight exposure may improve RACR.
Implications for Practice: Patients with esophageal and gastric cancer should be encouraged to engage in outdoor PA during the daytime as part of their regular lifestyle to maintain a robust circadian rhythm.
Competing Interests: The authors have no conflicts of interest to disclose.
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