An overview analysis of the time people spend outdoors

An important factor in determining our exposure to sunlight, and the consequent impact on skin health and vitamin D status, is the time we spend outdoors.

To determine estimates of the typical times per day spent outdoors during weekdays, weekends and holidays during a summer season.

A number of published studies giving data on the time per day spent outdoors by people were reviewed and a meta-analysis performed. From these data summary estimates of the average time per day outdoors were extracted.

Time spent per day outdoors during weekdays and weekends is positively skewed, with a normal distribution of times outdoors during holidays. The median times per day outdoors during weekdays and weekends gave pooled estimates of 1·04 and 1·64 h, respectively. Corresponding values for the pooled estimates of mean times outdoors during these two periods were 1·43 and 2·38 h. The mean time per day outdoors during holiday exposure is 5-6 h.

Summer-long distribution of times spent outdoors on a daily basis exhibits a highly skewed nature that highlights the difference between our adventitious and recreational exposure. Over the course of a summer season, when people are outside, they spend on average of 1-2 h per day outdoors.