When the President’s Commission on Americans Outdoors reviewed the nation’s policies on outdoor recreation in 1985, the social, economic, and environmental benefits of recreation were recognized, but little attention was paid to human health benefits. Since then, however, research has confirmed a link between physical activity that takes place outdoors and positive health outcomes—and also an association between an indoor, sedentary lifestyle and negative health consequences. There is also evidence that both being outdoors and viewing natural scenes can reduce stress. The links are sufficiently strong that researchers and practitioners in health- related fields are now beginning to identify parks and recreation as a health service.