title: Seasonality in physical activity and walking of healthy older adults.
abstract: BACKGROUND
  An increasing number of older adults require improvements in their quality of life. Physical activities, particularly walking ability, are of primary importance for older adults. The influence of season on physical activity has not been sufficiently studied among older adults. Therefore, this report compared the physical activity and walking of older individuals between summer and winter seasons using a longitudinal study design in a community in a mid-latitude area.
  
  
  METHODS
  Participants in the study comprised 39 healthy community-dwelling adults ranging in age from 65 to 80 years. Physical parameters and activities as well as the preferred speed of walking were measured at half-year intervals.
  
  
  RESULTS
  Significant seasonal differences from summer to winter and from winter to summer were detected. Specifically, body fat percentage, single-leg stance, walking speed, cadence, stride length, and trunk and head-trunk pitch ranges were greater in winter than in summer, whereas grip strength and steps per day were greater in summer. Temperature and total activity level were considered to be related to body fat percentage. Grip strength was thought to be affected by outdoor temperature. The possibility of relationships between increased activity per unit time in older adults and increased preferred walking speed, cadence, and stride length in winter temperatures was discussed.
  
  
  CONCLUSIONS
  The seasonal climatic environment of the geographic area of this study affected the activity level of the participants. These results indicate that seasonality should be considered when analyzing physical activity and walking in older adults.
authors.affiliation: University Museum, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo, 113-0033, Japan. tkimura@um.u-tokyo.ac.jp.|Ishikawa Prefectural Nursing Universtiy, 1-1, Gakuendai, Kahoku, Ishikawa, 929-1212, Japan. tkimura@um.u-tokyo.ac.jp.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Ishikawa Prefectural Nursing Universtiy, 1-1, Gakuendai, Kahoku, Ishikawa, 929-1212, Japan. kobayasi@ishikawa-nu.ac.jp.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Kitasato University, School of Nursing, 2-1-1, Kitasato, Sagamihara, Kanagawa, 228-0829, Japan. nakayama@nrs.kitasato-u.ac.jp.
authors.forename: Eijun
authors.initials: E
authors.lastname: Nakayama
authors.affiliation: Ishikawa Prefectural Nursing Universtiy, 1-1, Gakuendai, Kahoku, Ishikawa, 929-1212, Japan. kakihana@ishikawa-nu.ac.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Kakihana
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D057187:Independent Living; D008137:Longitudinal Studies; D008297:Male; D018670:Monitoring, Ambulatory; D012621:Seasons; D016138:Walking / Q000706:statistics & numerical data*