Physical Activity during Winter in Old-Old Women Associated with Physical Performance after One Year: A Prospective Study.

Background. The aim of this study was to evaluate whether the decline of physical activity during winter influences physical performances (after 1 year) in old-old women. Methods. Fifty-three Japanese women (mean age: 78.4 ± 3.2 years) participated in this study. Data of physical activity was collected by using an accelerometer at baseline and 3-month follow-up, and participants who decreased step counts in this period were defined as declining groups. We measured grip strength, knee extensor strength, total length of the center of gravity, hip walking distance, and maximum walking speed to evaluate physical performances at baseline and 1-year follow-up. Repeated-measures analysis of variance determined the difference in physical performance between declining groups and maintenance group with maintained or improved step counts. Results. Daily step counts for 22 older women (41.5%) decreased during winter. A statistically significant interaction effect between group and time was found for maximum walking speed (F(1,50) = 5.23, p = 0.03). Post hoc comparisons revealed that walking speed in the maintenance group significantly increased compared with baseline (p = 0.01); the declining group showed no significant change (p = 0.44). Conclusion. Change of physical activity during winter influences the physical performance level after 1 year in community-dwelling old-old women, particularly its effect on maximum walking speed.