When did everyone go indoors?
One study of American adults published in 2008 found them spending 25 percent less time in parks, forests or hunting and fishing than they did in 1987.
About the same time, a survey of adult activity levels found that two-thirds spend more than two hours a day watching TV or videos, and three-quarters said they had not walked or biked to work or to do errands in the past 30 days.
Too much sitting, by the way, can kill. New research published in July by the American Cancer Society found that women who reported sitting more than six hours a day were 37 percent more likely to die during a 13-year study period than those who sat fewer than three hours a day. The most sedentary men were 18 percent more likely to die than the more active.
A new report from the National Wildlife Federation on the importance of outdoor play for kids paints an even more dire picture: Surveys by researchers at the University of Michigan show that children are spending only four to seven minutes a day in unstructured outdoor play. By contrast, 8- to 18-year-olds are connected to some form of electronic media for eight to nearly 12 hours a day, according to a study done for the Kaiser Family Foundation.
Parents take children to soccer and horseback riding and lacrosse and Boy and Girl Scouts and scads of other organized activities. What there's not much of is free time — time for kids just to be kids — outside.
Playing outside without coaches or parents, but with other kids, fosters imagination and helps teach youngsters to share, cooperate and solve problems. It "demands of us that we create a fort out of a backyard, a tree house out of a tree and a bunch of old boards," said Dr. Michael Rich, director of the Center for Media and Child Health at Children's Hospital in Boston.
The salutary effects of time in nature don't always require free play, many studies show. Researchers in Britain reported in May a positive effect on the mental health of people who spent just five minutes a day in a park or woods walking, fishing, cycling, riding a horse and even doing farm chores.
Another British study, published in 2008, found that living near parks or woodlands improves health and extends the life span regardless of a person's social class or income.
"Nature is fuel for the soul," said Richard Ryan, a professor of psychology at the University of Rochester who led a series of studies published in June that found an energizing effect from nature even when experimental subjects only looked at photos of nature, looked out a window or imagined themselves outside.
"Often, when we feel depleted, we reach for a cup of coffee, but this suggests a better way to get energized is to connect with nature," said Ryan. His team found that being outside 20 minutes a day was enough to boost vitality.
Other studies have shown that being in a natural environment helps improve everything from wound healing and blood pressure to muscle tension, depression and attention deficit hyperactivity disorder.
The Wildlife Federation's new health report lays out the various benefits of outdoor play and urges everyone from parents to pediatricians to educators to take steps to get children outside on a more regular basis.
"Nature may indeed be the best kind of nurture," said federation executive vice president Jaime Matyas, who is coordinating a larger "Be Out There" campaign (www.beoutthere.org) for the federation and various partners.