Associations between objectively assessed physical fitness levels and sleep quality in community-dwelling elderly people in South China

Abstract

Purpose: The aim of this study was to explore associations between objectively assessed physical fitness levels and sleep quality in community-dwelling elderly people in South China.

Methods: One thousand one hundred thirty-six (504 males and 632 females) community-dwelling adults aged ≥ 50 years old in Dongguan City, South China, were included in the cross-sectional study. All the participants were asked to complete all prepared multi-instrument questionnaire, including the Pittsburgh Sleep Quality Index (Chinese version), for the assessment of the sleep quality and information regarding socio-demographic characteristics, lifestyle, and physical health data. Physical fitness was measured by grip strength, one-leg standing test (OLST) with eyes open, back scratch test, and the forced vital capacity (FVC).

Results: The percentage of poor sleep quality among elderly people (≥ 50 years old) was up to 18.2%. Lower FVC was associated with the poorer sleep quality (adjusted OR = 0.74 per SD increase; P = 0.009), and participants with lower performance in back scratch test were more likely to suffer poor sleep quality (adjusted OR = 1.17 per SD increase; P = 0.035). The independent contribution of physical fitness tests results on the risk of poor sleep quality was 22.1%.

Conclusions: Our results indicated that sleep quality was strongly associated with physical fitness among community-dwelling elderly people; the lower of the physical fitness predicted poorer sleep quality.

Keywords: Cross-sectional study; Physical fitness; Pittsburgh Sleep Quality Index; Sleep quality.