If you’ve ever felt more at ease after spending time in a park or walking through a forest, it’s not just in your head – your body is actually responding.

Being in natural environments can cause real, measurable effects within the body – such as reducing stress hormones, lowering blood pressure, and even supporting gut health.

You don’t need to go on a long hike to experience these benefits. Just 20 minutes outside is often enough to make a noticeable difference, so a quick walk to the park and eating lunch on a bench a few times a week can have a positive impact on both your mental and physical well-being.

Here are four ways that time in nature can boost your health:

1. You relax without trying

Your body reacts instinctively when you're surrounded by nature — whether it’s the sight of green foliage, the scent of pine, or the sound of birds and leaves swaying in the wind. These natural stimuli activate your autonomic nervous system, which manages the body’s automatic functions.

Even a brief visit to a local park can spark this response.

“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,” explained Baroness Kathy Willis, a professor of biodiversity at Oxford University.

A UK-based study with nearly 20,000 participants found that those who spent at least two hours each week in green spaces were significantly more likely to report being in good health and having greater psychological well-being.

With so much evidence backing nature’s health benefits, some regions have even trialed "green social prescribing," where individuals are encouraged to connect with nature to improve both their physical and mental health — with promising results for overall happiness and wellness.

2. Your hormone levels shift

Spending time outdoors doesn’t just calm your nerves — it also has an impact on your hormones.

Willis notes that exposure to natural settings activates the endocrine system, helping to lower stress-related hormones like cortisol and adrenaline.

“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.”

Natural killer cells are crucial for fighting off viruses, and in this study, participants maintained elevated levels of these cells even two weeks after being exposed to the forest scent.

As Prof Ming Kuo from the University of Illinois at Urbana-Champaign puts it, nature “calms what needs calming and strengthens what needs strengthening.”

She adds, “A three-day weekend in nature has a huge impact on our virus fighting apparatus and even a month later it can be 24% above baseline.”

Kuo also points out that even shorter sessions in green spaces can yield lasting, albeit smaller, effects on the body.

3. Scent is a strong trigger

The smells of nature are just as influential as its sights and sounds.

Plants and soil release natural compounds into the air, and as you breathe them in, some of those molecules can enter your bloodstream.

Willis highlights pine as a good example. Simply inhaling the aroma of a pine forest can lead to noticeable calmness within 90 seconds, and this effect can last around 10 minutes.

It’s easy to assume that this calming response is based on memory or personal associations, but research shows otherwise. In one study, even infants with no previous exposure to a calming scent showed a relaxed response when limonene – a compound linked to calm – was released into the room.

4. Nature supports your gut

Nature doesn’t just help your mind — it may also benefit your microbiome. Plants and soil are teeming with beneficial bacteria.

“They’re the same kinds of good bacteria we pay for in probiotics or drinks,” Willis explains.

Prof Ming Kuo has studied how exposure to nature affects things like susceptibility to infections and mental health. She notes that breathing in some of these microbes may elevate mood, and the antimicrobial compounds that plants release – called phytoncides – might also help the body resist illness.

Dr. Chris van Tulleken, an infection scientist, sees nature as a healthy challenge for the immune system that “tickles your immune system.”

He encourages his children to play in the dirt during forest visits, allowing the beneficial microbes to enter their systems through the nose and mouth.

Bringing nature to you

Of course, not everyone has immediate access to the great outdoors — but the good news is that even small touches of nature at home can have a soothing effect.

According to Willis, certain flowers, particularly white or yellow roses, have been shown to provide the strongest calming impact on brain activity.

To engage your sense of smell, try using a diffuser with essential oils like pinene, which may help promote a feeling of calm.

And if you're stuck indoors, even looking at a forest photo or something green can be beneficial.

Studies suggest that viewing images of nature on a screen or gazing out the window at greenery can trigger similar calming brainwave activity and help lower stress levels.

“Every bit seems to help,” says Prof Ming Kuo