Americans spend 87 per cent of their time inside buildings and a further 6 per cent inside vehicles. Neil Klepeis established that in 2001 from 9,386 24-hour diaries collected by telephone across the United States over two years, and the proportions held steady across regions and across a decade. Everything below happens inside that 87 per cent.
Birgit Wallmann-Sperlich followed twelve people out of a conventional office into one designed to be active and biophilic at once, surveying them a month before the move and three and seven months after. Standing time during office hours rose by about 40 minutes a day, at p below 0.01. Nothing else moved. Not work engagement, not satisfaction with the office, not performance.
Daniel Brown ran the most rigorous test in this group and most of it came out null. Ninety-four office workers at an international company were randomised in 2014 to a control group, to a lunchtime walk through trees and maintained grass, or to a lunchtime walk through housing estates and industrial areas, twice a week for eight weeks, and 73 finished. Resting autonomic function did not differ between the groups. Self-reported mental health rose by 2.7 SF-8 points in the nature group alone, with a confidence interval running from 0.0 to 5.4. Adherence was 42 and 43 per cent, and Brown concludes that two suggested active lunchtimes a week with little support is not enough to change anything.
Patrik Andreasson asked eight office workers in 2025 to do at least 30 minutes of their work outdoors every day for a week. They managed 322 minutes across the week, roughly 64 minutes a day, mostly in urban nature. Self-rated stress was 15 per cent below the previous week. It was significant on a paired t-test and not on a Wilcoxon test, and Andreasson reports both rather than choosing.
Margherita Pasini surveyed 57 employees of an Italian office through a move they helped design. A view connected with nature correlated 0.54 with job satisfaction. Areas set aside for destressing correlated 0.58 and natural light 0.50. The view ranked second of the three.
Tobias Ramm had 15 students from Cologne play a puzzle game indoors and outdoors in 2024. Groups finished in 103.2 seconds outdoors against 122.4 indoors, 15.68 per cent faster, while individual times moved by 2.89 per cent.
The samples on this sheet run 8, 12, 15, 57 and 94. Klepeis is the exception at 9,386, and it records where people are rather than what being there does to them.