Another study looked at changes in Chicago-area weather over 3 years and their impact on physical activity in older adults with arthritis. Again, data supported dramatic seasonal reductions in physical activity. For example, in November, the month with the lowest physical activity, adults were 38% less active than in June (the month with the highest physical activity). In addition, factors such as rain and snow, cold weather and shorter daylight hours were all associated with reductions in physical activity. Authors estimated that heavy rain reduced average physical activity by about 12%. Similarly, authors noted that “the 5.7 hour average decrease in daylight hours between January and June was associated with over 14% fewer daily activity counts, or almost 70 additional minutes of completely sedentary time.”
A comprehensive study of walking patterns in over 1300 German older adults found similar results. The change in global radiation between winter and summer increased average physical activity (walking) by almost 20 minutes/day in study participants, whereas a 10 degree increase in temperature augmented daily walking by about 7 minutes. The change in daylight hours from a short day (9 hours daylight) to a long day (16 hours daylight) resulted in a 12-13 minute increase in average daily activity. By contrast, wind speed, precipitation, and humidity all decreased physical activity patterns, as seen in the graph at right.
So, there’s no doubt that summer time is a fun time, with substantial increases in physical activity. But some additional patterns and behaviors– the incorporation of extra activities, the change in daylight hours, the reduction in stormy weather– also contribute to our exercise behaviors across the year.