Impact of season on the association between muscle strength/volume and physical activity among community-dwelling elderly people living in snowy-cold regions

Abstract Background Although the benefits of physical activity are well-known, levels of physical inactivity are increasing in many countries. Physical activity, particularly for preventive care of the elderly, must be encouraged. The level of physical activity undertaken by people is influenced by season; however, little is known about seasonal fluctuations of physical activity and its relation to muscle strength/mass. Consequently, we clarified the association between physical activity levels and muscle strength/skeletal muscle mass during non-snowy and snowy seasons in northern Japan. Methods Participants were community-dwelling elderly people aged 65 years or older living in Tobetsu, northern Japan. A 30-s chair-stand test (CS-30) and body composition measurements using bioelectrical impedance analysis were conducted prior to physical activity measurement using a three-dimensional acceleration sensor in both non-snowy and snowy seasons. Daily steps for the non-snowy and snowy seasons were compared using Welch’s t test. The association between the CS-30/skeletal muscle index and daily steps in both seasons was estimated by fitting multiple linear regression models, with age and sex as covariates. Results Average daily step counts were significantly lower during the snowy season, compared to the non-snowy season (P