Group nature walks are linked with significantly lower depression, less perceived stress and enhanced mental health and well-being, researchers said.
People who had recently experienced stressful life events like a serious illness, death of a loved one, marital separation or unemployment especially seemed to see a mood boost after outdoor group walks.
"We hear people say they feel better after a walk or going outside but there haven't been many studies of this large size to support the conclusion that these behaviours actually improve your mental health and well-being," said senior author Sara Warber, associate professor of family medicine at the University of Michigan Medical School.
"Our findings suggest that something as simple as joining an outdoor walking group may not only improve someone's daily positive emotions but may also contribute a non-pharmacological approach to serious conditions like depression," said Warber.
Researchers evaluated 1,991 participants from the Walking for Health programme in England, which helps facilitate nearly 3,000 weekly walks and draws more than 70,000 regular walkers a year.
"Group walks in local natural environments may make a potentially important contribution to public health and be beneficial in helping people cope with stress and experience improved emotions," said Warber.