Nature and Health

Being in nature is good for our health and well-being. Recent research is showing what happens in our brains and bodies when we interact with nature, as described in Kathy Willis' new book Good Nature. There are benefits from what we see, smell, hear and touch.

When we look at nature, our heart rate and blood pressure fall, stress hormones like adrenalin decrease, and our brainwave activity shows we are calmer and more clear-minded. Patients recovering from surgery recover three times faster and need less pain medication if they see greenery from their window. Physiological markers of calmness are higher with green-and-white leaves and yellow or white flowers, while preferences lean towards radially symmetrical or blue flowers.

The best landscape visually is open with a few scattered trees. It provides general background attention rather than focused attention, giving a mental mini-break. Our eyes respond to the fractal dimension of complexity, with mid-fractal complexity resulting in brainwaves with heightened alpha and beta frequencies and reduced delta frequencies associated with increased focus and a feeling of calm.

When you smell a plant scent, it passes across your lung membrane into your blood, and many scents affect biochemical pathways in the same way a prescription drugs, often with long-lasting effects. Lavender contains linalool, which has anti-anxiety effects. Pinene from pine forests also reduces stress. Plants in the cypress family have sesquiterpinoids that increase activity in the parasympathetic nervous system indicating relaxation, but also reduce adrenalin and elevate immune cells that attack cancers and viruses. Limonene in citrus fruits is an anti-inflammatory molecule.

Sounds are known to calm us. Birdsong reduces physiological symptoms of stress, while water sounds improve mood and cognitive performance. Bad sounds like the squawking of a crow or parrot do not relax us. Listening to nature sounds during an operation with epidural anaesthesia leads to lower levels of a stress-related enzyme indicative of pain.

Touching wood lowers your blood pressure, and feet touching wood is calming, with different responses depending on the kind of wood. Children planting plants in the classroom perform better academically and feel calmer and happier than those playing a planting game on a smartphone.

The environmental microbiome of bacteria and viruses in the air is richer in naturally biodiverse areas, reducing non-communicable diseases like asthma and allergies. Children playing in soil from a boreal forest, or adults with a green wall in their office, had more good bacteria on their skin and in their gut, with reduced inflammatory markers in their blood.

To maximise the benefits, spend at least 20 minutes at a time in nature, and at least 120 minutes each week, walking in a park away from unhealthy road sounds, or where you can smell scented plants and hear the birds. Avoid dense tree cover as it can stress you out.

Gardening has huge benefits as it combines sight, sound, smell and touch in contact with the environmental microbiome. Gardening in your front yard is better than your back yard as you walk through it more, and gardening in a allotment is better that your private garden because of community cohesion and the variety of plantings all year round.

In homes and offices, plants add sight and smell. Increase the amount of natural untreated wood. Look out the window on greenery. Schools also need greenery, with trees providing shade as well. There is some evidence that prescribing nature in hospitals can be as cost-effective and effective in terms of treatment as prescription drugs. More biodiversity in cities is good for nature and for our well-being.

SOURCE: 'Certain landscapes, flowers and trees are better for our health than others', Kathy Willis interviewed by Kate Douglas, New Scientist 31 August 2024, pp.41-43