Plants have a strong and enduring reputation as a positive influence on our mood and behavior, and so a recent Japanese study from the University of Hyogo should perhaps come as no surprise.  It found that even a small plant can have a positive impact on the stress levels of workers.

The researchers examined the use of indoor plants in supporting the mental health of workers who are not traditionally exposed to greenery in their work.

Stress reduction

Stress is at almost epidemic levels in the workplace, so employers the world over are looking for effective and efficient ways of buffering stress levels among workers.  The positive impact of plants on our mental wellbeing is fairly well known, but the new paper aims to quantify the scale of the impact.  As such, they conducted their work in a real office environment rather than the lab.

“At present, not so many people fully understand and utilize the benefit of stress recovery brought by plants in the workplace,” the researchers explain. “To ameliorate such situations, we decided it essential to verify and provide scientific evidence for the stress restorative effect by nearby plants in a real office setting.”

The researchers measured psychological and physiological stress both before and after placing plants at the desks of workers.  The study contained both a control period with no plants present, and an intervention phase when the employees were asked to care for a small plant on their desk.

Stress was measured according to the State-Trait Anxiety Inventory, which is a commonly used measure of trait and state anxiety.  Each participant was asked to take a 3-minute rest when they felt stressed or tired, and the researchers measured the rate at which their pulse lowered after that rest.

Something to care for

Each participant was given one of six plants they could keep on their desk, including bonsai plants, foliage plants and air plants.  Each volunteer chose a plant and kept it near the monitor on their desk.  They were given the option of either having a passive involvement with their plant (ie just looking at it) or taking a more active role in its care.

The results showed that the plants seemed to have a calming effect on participants, with anxiety levels significantly lower after the intervention than they were prior to it.  What’s more, the results were consistent regardless of the age of participants or the plants they chose to tend.  The researchers believe the results suggest more greenery in the office could be a low cost intervention to help employees manage stress.

While the Hawthorne Effect was at the back of my mind as I read the study, it is nonetheless part of a growing canon of work highlighting the benefits of plants in the workplace, so does perhaps warrant further attention.