Veterans were surveyed before and after a multi-day wilderness recreation experience, which involved camping and hiking in groups of between six and 12 participants. More than half of participants reported that they frequently experienced physical or mental health problems in everyday life.

One week after the experience, veterans reported a greater than 10 percent improvement in several measures of psychological well-being, a 9 percent increase in social functioning, and a nearly 8 percent gain in positive life outlook. In some cases, the results persisted over the next month.

"The findings suggest that extended group-based nature recreation can have significant positive impacts on veterans struggling with serious health problems," said Jason Duvall, a research scientist at the U-M School of Natural Resources & Environment and one of the study's lead authors. "Although more research is needed and many questions remain, the use of extended group-based outdoor recreation programs to ease veterans' transition back into civilian life seems to be a promising approach."

The Sierra Club, a grassroots environmental organization, operates the Military Family and Veterans Initiative, which focuses on providing military service members and their families with access to outdoor experiences. The Sierra Club wanted to know whether these efforts were making a difference in the lives of veterans. The organization commissioned the study and selected SNRE because of prior research by Duvall and co-author Rachel Kaplan, a professor at SNRE, on the links between mental health and contact with nature. While both anecdotal and experimental data suggest exposure to green environments is beneficial, few studies have examined the impacts of these programs on veterans specifically.

"The Sierra Club knows anecdotally the mental, emotional and physical benefits that come from spending time in nature, particularly for returning service members for whom the outdoors can be integral to their reintegration," said Stacy Bare, Sierra Club mission outdoors director. "The results of the University of Michigan's study reinforce these beliefs and support our efforts to make these types of experiences available to more people."

Comments by veterans supported the survey conclusions.

"This trip helped me to reevaluate what's important in life," said Tim, a 52-year-old Navy veteran. "It was nice to live a week without being 'plugged in' and take in the great outdoors."

"It helped me to remember who I was and enjoy something I haven't in a long time," added Dan, a 39-year-old Army veteran.

Helping veterans cope with these issues has become important in recent years given the demands placed on military personnel and their families. In response, a number of outdoor recreation groups such as the Sierra Club, through its Military Families and Veterans Initiative, developed group-based nature recreation programs targeting veterans. Veterans may identify more strongly with activities outdoors that involve physical challenge, camaraderie and achievement of an objective -- experiences that are shared with their military service. As a result, the approach used by these programs may be more appealing than conventional clinical treatments when it comes to dealing with mental health issues. "The excursions are a supportive environment because in many ways, they recreate many positive aspects of the military experience," Duvall said. "They are outside, in a group, sharing similar mental models and, in a sense, on a mission. In that scenario, the impact of the natural environment might be heightened."

The Sierra Club chose four partner organizations as part of the study group: Higher Ground (Sun Valley, Idaho), Wasatch Adaptive Sports (Snowbird, Utah), Wilderness Inquiry (Minneapolis, Minn.), and Women's Wilderness Institute (Boulder, Colo.). Combined, the groups offered 12 programs lasting four to seven days. The excursions generally did not include formal, structured psychological counseling or therapy. Instead, the emphasis was on the outdoor programs, from fly-fishing, kayaking and whitewater rafting to backpacking and paddling.

The study sample was 98 veterans. They were surveyed one week before, one week after, and about one month after participating. In addition to assessing demographic and background information, the survey itself measured changes in psychological well-being, social functioning, life outlook, and activity engagement over time.

Another key result was that after the experience, veterans were more likely to take part in activities that involved exploration (such as learning new things or testing abilities) and helping others. The changes in well-being were also particularly strong for veterans who had initially reported more severe ongoing health issues, with the magnitude of improvements often 1.5 times that of those with less serious health problems.

"Veterans with more serious health problems seemed to benefit most," Duvall said.