Spending a short amount of time in nature can have a powerful impact on both physical and mental wellbeing, scientists say.
Even a brief walk in a park or time spent outdoors can trigger measurable biological changes, including reduced stress levels, lower blood pressure and improved gut health, reports BBC.
Experts note that the benefits do not require long hikes or extended trips. Research suggests that around 20 minutes in a natural setting is enough to produce noticeable effects, making simple activities like a lunchtime stroll or sitting on a park bench worthwhile.
Unconscious relaxation response
Exposure to natural sights, sounds and smells—such as greenery, birdsong and rustling leaves—activates the autonomic nervous system, which controls unconscious bodily functions.
This response can occur even during a visit to a local park. “We see changes in the body such as a lowering of blood pressure, a change in your heart rate variability and your heart beats slower – all associated with physiological calming,” Baroness Kathy Willis, a biodiversity professor at Oxford University, told BBC Radio 4’s *What’s Up Docs?* podcast.
A UK study involving nearly 20,000 participants found that those who spent at least 120 minutes a week in green spaces were more likely to report better health and improved psychological wellbeing.
The growing evidence has also led to initiatives such as green social prescribing, which connects people with nature to enhance physical and mental health outcomes.
Hormonal balance improves
Time outdoors also influences the body’s endocrine system. According to Willis, nature exposure reduces cortisol and adrenaline—hormones associated with stress and anxiety.
“A study found that people in a hotel room for three days who were breathing in Hinoki (Japanese cypress) oil saw a big drop in the adrenaline hormone and a large increase in natural killer cells in their blood.”
These natural killer cells help the body fight viruses, and elevated levels remained even two weeks after exposure.
Ming Kuo from the University of Illinois at Urbana-Champaign explained the broader effect,
“Essentially nature ‘calms what needs calming and strengthens what needs strengthening,'” she told the BBC.
“A three-day weekend in nature has a huge impact on our virus fighting apparatus and even a month later it can be 24 percent above baseline.”
She added that shorter exposures also produce smaller but lasting benefits.
Power of natural scents
The sense of smell plays a crucial role in nature’s calming effect. Organic compounds released by plants can enter the bloodstream when inhaled.
Willis highlighted pine forests as an example, noting that their scent can induce calmness within 90 seconds, with effects lasting up to 10 minutes.
Research also shows that the response is not purely psychological. Even infants, with no prior associations, displayed calming reactions when exposed to limonene, a naturally soothing scent.
Boosting gut health and immunity
Nature can also enrich the body’s microbiome. Soil and plants contain beneficial bacteria similar to those found in probiotics.
“They’re the same kinds of good bacteria we pay for in probiotics or drinks,” Willis explained.
Kuo’s research indicates that inhaling certain microbes may improve mood, while plant-released antimicrobial compounds, known as phytoncides, can help combat disease.
Chris van Tulleken described nature as a “positively challenging environment” that supports immune function. He encourages children to interact with natural elements like soil, which can enter the body through the nose or mouth and stimulate immune responses.
Bringing nature indoors
While access to forests or parks may not always be possible, experts say small indoor changes can still offer benefits.
Visual elements such as flowers—particularly white or yellow roses—have been shown to produce calming effects on brain activity. Similarly, essential oils like pinene can recreate natural scents indoors.
Even indirect exposure can help. Studies suggest that viewing images of nature or looking at greenery through a window can trigger calming brainwave patterns and reduce stress.
“Every bit seems to help,” said Ming Kuo.
