Nature calms our stressed-out soul. Nature is the best medicine, but new research is showing how little time we need to set aside to harvest the benefits.
In one new study, researchers tried to find the most effective "dose" (药剂) of nature within the context of normal daily life. As more doctors prescribe (开药方) nature experiences for stress relief and other health benefits — sometimes referred to as a "nature pill"— the study's authors hoped to make the details of these treatments clear.
"We know that spending time in nature reduces stress, but until now it is unclear how much is enough, how often to do it, or even what kind of nature experience will benefit us," says lead author MaryCarol Hunter in a statement. "Our study shows that for the greatest payoff, in terms of efficiently lowering levels of the stress hormone cortisone (压力荷尔蒙激素), you should spend 20 to 30 minutes sitting or walking in a place that provides you with a sense of nature."
A nature pill can be a low-cost, low-risk way tocurbthe negative effects of urbanization and indoor lifestyle. To find the most efficient dosage, Hunter and her co-authors asked 36 city citizens to have nature experiences of at least 10 minutes three times per week over eight weeks.
Every two weeks, the researchers collected saliva (唾液) samples to measure levels of the stress hormone cortisone, both before and after the participants took a nature pill. The data showed that just a 20-minute nature experience was enough to significantly reduce cortisone levels. The effect was more efficient between 20 and 30 minutes, after which benefits continued to increase but at a slower rate.
That fits with the findings of another recent study, which found that spending 20 minutes in an urban park can make you happier, no matter whether you use that time to exercise.
For this study, 94 adults visited 3 urban parks in Mountain Brook, Alabama, completing a questionnaire about their subjective well-being before and after their visit. An accelerometer (加速计) tracked their physical activity.
A visit lasting 20 to 25 minutes showed the best results, with a roughly 64% increase in the participants' self-reported well-being, even if they didn't move a great deal in the park. That last point is particularly positive, since it means anyone can benefit from visiting a nearby park, whatever his or her age or physical ability.
"There is increasing pressure on green space within urban settings," said a UAB professor Gavin Jenkins. "Planners and developers look to replace green space with residential (住宅的) and commercial property. The challenge facing cities is that there is increasing evidence about the value of city parks but we continue to see the disappearance of these spaces."
