Data on the physical activities of 1,252 people of different ages, genders and mental health status in the United Kingdom explored the relationship between outdoor “green exercise,” mood and self-esteem. Large benefits to mood and self-esteem occurred in short time periods of only five minutes, with the benefits diminishing but still positive over longer periods of time. Mood and self-esteem improved in all environments, especially where water was present. Experiment: Walk one day on your treadmill at home and then walk the next day outside. Enough said!!