Heads up, retirees: Volunteering on environmental projects could not only prompt you to get more exercise but also improve mental and physical health through old age, according to a new Cornell study published online in The Gerontologist (Feb. 19).

The study found that environmental stewardship is strongly linked to greater physical activity, better self-rated health and fewer symptoms of depression over a period of 20 years. In fact, the researchers found that environmental volunteers are half as likely as non-volunteers to show depressive symptoms 20 years later, whereas other forms of volunteering lower one's risk by roughly 10 percent.

What's more, environmental volunteers gain more dramatic health benefits compared with people engaged in other types of service, according to the study, which was conducted by researchers in the College of Human Ecology (CHE) and Weill Cornell Medical College.

"It's very rare in society that we get to address two problems at once," said lead author Karl Pillemer, professor of human development and CHE associate director of outreach and extension "As baby boomers retire, they [create] a vast untapped resource to help improve our natural environment, which is a pressing need right now. The bonus is that by doing so they also gain substantial health benefits."

The authors analyzed data collected between 1974-1994 from the Alameda County (Calif.) Study, an examination of health and mortality that followed nearly 7,000 adults since 1965. They note that this is the first study to examine the health benefits of environmental volunteering in a large population over an extended period of time, unlike past studies that have focused on a one-time survey or data set.

Pillemer, who with Cornell researchers Linda Wagenet and Rhoda Meador launched an environmental stewardship training program for retirees in 2008, said the findings could prompt more conservation groups to embrace older volunteers.

"We associate environmental activism with younger adults, but it carries tremendous rewards for older adults," he said. "In addition to the benefits to physical health from being in nature, protecting the environment also helps older adults gain a sense of generativity, the notion of working to achieve something for the good of future generations. They can help the Earth and at the same time help themselves."

Co-author Nancy Wells, associate professor of design and environmental analysis, called the link between environmental service and improved physical and mental health "quite compelling."

"Time spent outdoors in the natural environment is a critical factor linking volunteering to the health outcomes observed in this study," Wells said. "Prior studies have shown that views of -- and time spent in -- the natural environment are associated with a variety of positive health outcomes, including cognitive functioning, psychological well-being and physical activity levels."

The researchers suggest further research to determine whether conservation activities could benefit older adults suffering from chronic conditions and persistent pain and to better understand the connection between such volunteering and health outcomes.

The study was funded by the National Institute on Aging. Co-authors include Dr. Cary Reid, geriatrician at Weill Cornell, and Thomas E. Fuller-Rowell, Ph.D. '10, a postdoctoral research fellow at the University of Michigan.

Ted Boscia is assistant director of communications for the College of Human Ecology.