UK adults exhibit higher step counts in summer compared to winter months

Background: Seasonal differences in step counts have been observed in a limited number of studies conducted on US adults. Due to the diverse global climate, assessment and interpretation of seasonal patterns in ambulatory activity may vary between countries, and regionally specific studies are necessary to understand global patterns. Currently, no studies have assessed whether a seasonal trend is present when ambulatory activity is measured objectively in adults living in the UK. Aim: To investigate whether pedometer-determined step counts of adults living in the UK vary between summer and winter. Subjects and methods: Ninety-six adults (52% male, age = 41.0 ± 12.3 years, BMI = 26.1 ± 5.1 kg/m2) completed a within-subject bi-seasonal pedometer study. All participants completed two four-week monitoring periods; one during the summer and one the following winter. The same Yamax SW-200 pedometer was worn throughout waking hours during both seasons, and daily step counts were recorded in an activity log. Intra-individual seasonal changes in mean daily steps were analysed using a paired samples t-test. Results: Summer mean daily step counts (10417 ± 3055 steps/day) were significantly higher than those reported during the winter (9132 ± 2841 steps/day) (p < 0.001). A follow-up study conducted the subsequent summer in a sub-sample (n = 28) reinforced this trend. Summer step counts were significantly higher than winter step counts on all days of the week (p ≤ 0.001). A significant day of the week effect was present in both seasons, with step counts reported on a Sunday being on average 1,500 steps/day lower than those reported Monday through to Saturday. Conclusion: Step counts in the sample of UK adults surveyed decreased significantly in the winter compared to the summer, suggesting future pedometer surveillance studies should capture step counts throughout the year for a non-biased reflection of habitual ambulatory activity. Public health initiatives should target these seasonal differences and opportunities should be provided which encourage individuals to increase their activity levels during the colder, darker months of the year.