This study (2011) reports the effects of different kinds of nature contacts to stress and stress-related health complaints. 503 office workers took a 10-15 minute online survey, and their contact to nature was measured in three different classes: outdoor nature contact, indoor nature contact (i.e. view from a window, natural light, live plants), and indirect nature contact (i.e. view to photographs of nature, recorder nature sounds).

The study found that nature contact had a link to stress and general health complaints: as workday nature contact increased, the perceived stress and health complaints decreased.

Higher nature-contact scores represented more nature contact at work, and lower perceived stress and health scores represented less stress and fewer health concerns. The three levels of nature connections correlated with health accordingly:

• The most direct nature contact, outdoor nature contact, had the strongest association with the positive effects (r for: stress=–0.17*; health complaints=–0.17*)
• Indoor nature contact had the second strongest association (r for: stress=0.04; health complants=–0.10*)
• Indirect nature contact had the least strong association (r for: stress=–0.08; health complaints=0.00)

*statistically significant result