The Surprising Impact of Too Much Greenery: When Indoor Plants Become a Stress Factor
We all know that bringing nature indoors can boost our mood and enhance our well-being. But what happens when we take it a step too far? A recent study by Stanford engineers reveals a surprising twist: too much greenery can actually increase stress levels.
Imagine if nature were a pill. You'd want to take it as needed, right? Well, a dose of nature, whether it's a quick walk in the park or a week-long camping trip, is generally good for us. But this new study shows that the relationship between indoor nature and well-being is more complex than we thought.
The researchers developed a clever way to measure different amounts of greenery and wood, and how they affect our stress levels. They found that while a few potted plants and a window with a tree view can make us feel refreshed and connected, too much greenery can actually make us feel overwhelmed and stressed.
"I was really surprised by the results," said the study's lead author, Eva Bianchi. "Around 60% total greenery and wood had the highest stress increase, which contradicted previous studies."
Measuring Nature's Dose
Past research has shown that indoor plants and natural materials reduce stress and boost feelings of restoration and belonging. But these studies often compare people's responses to nature versus no nature, or use subjective measures like 'small', 'medium', and 'large' amounts of plants.
"There's a lot of research out there, but it's hard to compare because no one uses the same methods," said senior author Sarah Billington. So, the Stanford team wanted to explore how people respond to different amounts of indoor nature, or what they call 'nature doses'.
To do this, Bianchi created a tool called Nature View Potential, which calculates how much nature you see in a room. Imagine standing in a room and imagining rays extending from your eyes. The tool measures how many of those rays are seeing natural elements.
Using this tool and 3D modeling software, the researchers designed digital conference rooms with different levels of wood, greenery, and nature views. They then asked 412 participants to spend time in these rooms, without them knowing they were being tested.
The researchers introduced stressors and measured participants' well-being before and after their tasks. They found that a greenery dose of around 20% had the strongest positive effect on restoration and a sense of belonging. But too much greenery, around 60%, led to increased stress.
The Perfect Greenery Balance
The study highlights that there's a sweet spot for indoor greenery. Too little doesn't seem to help much, but too much can be overwhelming. Some participants even commented on feeling stressed by the abundance of plants.
Interestingly, wooden furniture and features alone didn't affect well-being. The researchers suspect this might be because the digital rendering wasn't realistic enough. Previous studies have shown benefits of wood, but perhaps the digital version in this study didn't capture that effect.
The findings show that our connection to nature is key. When participants felt a connection to nature, they benefited more from the greenery. But when they didn't feel that connection, the natural features had little impact.
"It's not just about putting plants in a room," Bianchi explained. "You need to make sure the nature in the room will help people feel connected to nature."
Looking Ahead
The researchers hope their findings will help designers create healthier indoor spaces, from homes to offices. They're also interested in understanding how our connection to nature varies and how we can bring the benefits of nature indoors, even in urban areas.
"How do you get the feeling of nature indoors?" Billington asks. "That's why quantification is so important. It helps us compare studies and make faster progress."
The study's findings are a reminder that balance is key. Too much of a good thing can sometimes be a bad thing, even when it comes to nature.
