Why Gardening Is Good for Your Health
A recent study in the Netherlands suggests that gardening can fight stress even better than other relaxing leisure activities. After completing a stressful task, two groups of people were instructed to either read indoors or garden for 30 minutes. Afterward, the group that gardened reported being in a better mood than the reading group, and they also had lower levels of the stress hormone cortisol.
"We live in a society where we're just maxing ourselves out all the time in terms of paying attention," says Andrea Faber Taylor, Ph.D., a horticulture instructor and researcher in the Landscape and Human Health Laboratory at the University of Illinois at Urbana-Champaign.
Humans have a finite capacity for the kind of directed attention required by cell phones and email and the like, Taylor says, and when that capacity gets used up we tend to become irritable, error-prone, distractible, and stressed out.
Fortunately this "attention fatigue" appears to be reversible. Following a theory first suggested by University of Michigan researchers in the 1980s, Taylor and other experts have argued that we can replenish ourselves by engaging in "involuntary attention," an effortless form of attention that we use to enjoy nature.
Trading your BlackBerry for blackberry bushes is an excellent way to fight stress and attention fatigue, Taylor says, as the rhythms of the natural environment and the repetitive, soothing nature of many gardening tasks are all sources of effortless attention.
"The breeze blows, things get dew on them, things flower; the sounds, the smells," says Taylor, herself a home gardener. "All of these draw on that form of attention."
Better mental health
The effortless attention of gardening may even help improve depression symptoms.
In a study conducted in Norway, people who had been diagnosed with depression, persistent low mood, or bipolar II disorder spent six hours a week growing flowers and vegetables. After three months, half of the participants had experienced a measurable improvement in their depression symptoms. What's more, their mood continued to be better three months after the gardening program ended.
The researchers suggest that the novelty of gardening may have been enough to jolt some of the participants out of their doldrums, but some experts have a much more radical explanation for how gardening might ease depression.
Christopher Lowry, Ph.D., an assistant professor of integrative physiology at the University of Colorado at Boulder, has been injecting mice with Mycobacterium vaccae, a harmless bacteria commonly found in soil, and has found that they increase the release and metabolism of serotonin in parts of the brain that control cognitive function and moodmuch like serotonin-boosting antidepressant drugs do.
Digging in the dirt isn't the same as taking Prozac, of course, but Lowry argues that because humans evolved along with M. vaccae and a host of other friendly bugs, the relative lack of these "old friends" in our current environment has thrown our immune systems out of whack. This can lead to inflammation, which is implicated in a host of modern ills, from heart disease to diabetes to depression.
"By reintroducing these bacteria in the environment, that may help to alleviate some of these problems," Lowry says.