New York, March 20 (IANS): Even city life can become a lot less stressful with a "greening treatment" of vacant spaces that includes cleaning and removing debris besides planting grass and trees, new research suggests.

"Our goal was to scientifically explore the connection between city environments and stress," said the study's lead author Eugenia South from the University of Pennsylvania.

"We used heart rate as a physiologic marker of acute stress, and the reduction we found suggests a biological link between urban blight reduction strategies like vacant lot greening and reductions in stress," South noted in the study published online by the American Journal of Public Health.

The researchers used a heart rate monitor with GPS to measure the stress response in study participants in two randomly selected Philadelphia neighbourhoods as they went on a prescribed walk.

Vacant lots in one neighbourhood randomly received a greening treatment, while the other neighbourhood served as a control and received no treatment.

Participants walked past vacant lots before, and then three months after the greening treatment of randomly selected lots.

The greening treatment is a low-cost environmental improvement that includes cleaning and removing debris, planting grass and trees, and installing a low wooden post-and-rail fence.

The average heart rate reduction attributable to being in view of the greened lots was over five beats per minute (bpm) lower than when near non-greened lots.

The researchers found that proximity to greened lots resulted in lower heart rates.

Heart rate change has been used in a few previous studies to evaluate acute stress response.