Can nature make us healthier? Laura King looks at whether a dose of nature can be the right medicine.
We all know that pollution is bad for us. You wouldn’t drink from a dirty river or walk through a smog-filled city without noticing the impact. When polluted, our environment can cause disease and death: according to the World Health Organization (WHO), polluted air kills 4.2 million people globally, and an estimated 842,000 people die each year from diarrhoea as a result of unsafe drinking water.
Noise too, has an impact. In its 2011 report, Burden of Disease from Environmental Noise, the WHO estimated that no less than one million healthy years of life are lost each year in Europe due to noise pollution — not including the impact of noise from industrial workplaces. Traffic is one of the worst offenders: our ears never switch off, and so continual noise can trigger the bodies acute stress response, raising our heart rate and blood pressure. As a result, many think that noise is perhaps the second-highest threat to public health after air pollution.
Practically, we depend on nature for the services it provides — air, food and water, to name a few — and clearly a well-functioning, unpolluted environment is better for us. However, evidence is also building to show that over and above a very practical need, our environment can provide numerous benefits to our health and happiness.
Reconnecting and evolution
In most cultures past and present there is evidence of a fondness for nature: in the UK we are a nation of pet-lovers; tomb paintings in ancient Egypt showed that people brought plants indoors. Our attraction to living things has led to the development of the Biophilia Hypothesis: the idea that humans possess an innate tendency to seek connections with nature and other forms of life.
This connection is thought to be beneficial for our health. Logically, we evolved within natural environments and a connection was needed to avoid us dying from exposure, hunger or disease. It’s therefore no surprise that a disconnect from the world around us doesn’t sit well with our evolutionary make-up, and reconnecting help solve many modern health problems.
One example is the emerging science surrounding circadian rhythms. Our bodies have evolved to be intrinsically linked to the earth’s day–night cycles and so we function better when we respect these. Eating in sync with our body clock has been shown to reduce metabolic disorders, such as diabetes, and reduce depression and inflammation. Similarly, exposing ourselves to artificial blue light from screens at night reduces the production of melatonin (the sleep hormone), as blue light is naturally found in the morning and so the body thinks it needs to stay awake. This natural reaction to a man-made environment reduces our ability to sleep, causing numerous health problems.
Spring in your step
We have not just altered our environment to one that is on-the-go 24 hours a day. Technological advances have also changed how we sustain ourselves, meaning that for many of us our daily life is very different from what it would have been a couple of hundred years ago. No longer do we all need to work the land — many of us are now sitting in offices and relatively sedentary. As a result, it comes as no surprise to most of us that we need to do more exercise, but is exercise outdoors better for us?
It would seem that it is. Pockets of green space in urban environments (eg parks or woodlands) have been shown to reduce stress and help us exercise more. Indeed, researchers from the Universities of Bristol and East Anglia found that those who lived closer to green space were more likely to exercise, while those who lived the furthest away from green parks were 27% more likely to be overweight.
Furthermore, studies have shown that people who live within 500m of green space are 24% more likely to get the recommended 30 minutes of exercise each day. Not only that, but exercising in natural spaces is also better for your mind. A study published in Environmental Science and Technology showed that people exercising outdoors reported lower feelings of stress and anxiety than those doing exactly the same activity indoors.
However, before you trade in your gym pass for a train season ticket to get out of town, nothing is ever completely clear-cut, and proximity to green space is no different. Access to such environments is often tied up with a number of other social-economic factors — namely those living close to green space are often less likely to experience deprivation. As a result, it might well be the case that the reported levels of happiness are at least partially due to a lack of other troubles.
However, anecdotal evidence, and an increasing number of studies suggest otherwise. This corresponds with what most of us already know. Who hasn’t taken in a view, breathed in a lungful of fresh air, and not felt instantly better?
What doesn’t kill you...
The outside is increasingly viewed as dirty. We use anti-bacterial sprays in our kitchens, do our utmost to stop mud coming into our houses, and polite society often demands a certain level of grooming and cleanliness.
Although staying clean is certainly important for hygiene, a little bit of dirt is actually good for us especially when we are growing up. It’s actually the case that fewer than 5% of all microbes cause disease, and it is thought that the presence of “good bacteria” on human barriers (such as the skin, gut and airways) strengthens our immune system and protects us from inflammatory disorders and allergies including asthma, allergic reactions and type 1 diabetes.
As with nature in general, a greater variety of species is a good thing. Microbes are no different, and hosting a diverse range of bacteria has been shown to improve the health of the gut, which in turn is thought to lower incidents of illnesses such as heart disease, liver disease, cancer and diabetes.
However, in an increasingly urbanised world, we are simply not being exposed to environments rich in bacterial species. This is one of the reasons why it is thought that incidents of various inflammatory conditions, such as asthma, are increasing.
This idea has been variously described as the Biodiversity Hypothesis, the microbial old friend mechanism, and the high microbial turnover mechanism. According to the hypothesis, population growth and urbanisation has led to a loss of biodiversity in our environment, leading to limited exposure to a diverse range of bacteria. This in turn results in poor human microbiota which then leads to immune dysfunction and more inflammatory diseases.
However, although clear links have been made to an urban environment and an increase in these illnesses, very little is known about the interactions between the biodiversity of life on the planet and our own microbiota. For example, it is not known how landscape-scale biodiversity directly relates to human health, whether some environments are more beneficial than others, or how these protective bacteria compare with other drivers of human health, eg socio-economic status and diet.
Nature to the rescue
Although many questions remain unanswered, there is a growing momentum behind nature-based solutions to enhance our health and wellbeing. These fall into two broad camps: bringing nature to the people through better planning and greening of public and civic spaces such as parks, hospitals or schools; and bring people to nature by encouraging nature-based activities.
A dose of nature
The concept of nature-based therapies is not new: the Romans had spa baths to enhance health, and during the Victorian era doctors advocated the therapeutic powers of sea water and air leading to an expansion in seaside resorts around the country. Sadly, with the growth of modern medicine, many of these nature-based remedies fell out of favour.
However, the tide is turning and green prescriptions are one way health professionals are starting to coax people back into the countryside. A green prescription, or nature-based health intervention, is defined as: “A prescription for a monitorable activity that involves spending time in natural environments for the benefit of human health and wellbeing”. Examples would include taking a walk in natural surroundings, bird-watching, gardening or taking part in conservation activities.
The concept of green prescriptions originated in New Zealand, and they have been shown to be largely successful. Studies of the approach published in the British Medical Journal found that over a 12-month period green prescriptions did indeed increase physical activity levels and improve quality of life. It didn’t always work for everyone, but 1 person in 10 maintained 150 minutes of vigorous activity a week which gave them an impressive 20–30% risk reduction in all-cause mortality.
The prescriptions were popular with patients, too. Surveys taken from people participating in the programme showed that six to eight months after getting a green prescription, nearly three-quarters noticed positive changes in their life, and nearly half had lost weight.
Green prescriptions are still an emerging field in the UK, but are becoming more commonplace. Unfortunately, unlike initiatives such as exercise on prescription, there is still not a standardised framework for patient evaluation and as a result there are a number of different models and referral processes. However, trials have taken place throughout the UK, and there is a growing movement in Scotland.
For example, in April 2019, Dundee Green Health Partnership (DGHP) started a Green Health Prescription trial across a number of GP surgeries. The trial formalises green prescription referrals, providing a way for healthcare professionals to signpost patients to nature-based interventions. The referrals will be treated in the same way as a normal prescription, and will even be printed on prescription paper.
Scotland is relatively forward-thinking in its use of nature to heal. Thought to be the first of its kind, NHS Shetland also formally adopted a referral scheme on the island last October. The green prescription programme is a joint initiative with the RSPB, and following a successful trial in one surgery has now been rolled out to 10 GP practices across Shetland.
Planning nature in
Bringing nature to the people is also fundamental if we are to have a fighting chance to reconnect with our natural surroundings. In this regard, planning is possibly the oldest form of environmental protection and promotion: done right it can foster our natural surroundings; done badly it can pollute and suffocate. Consequently, our planning policies are fundamental if we are to start incorporating green and blue spaces into our urban environments.
The concept of biodiversity net gain is one way in which the Government is intending to promote sustainable and greener developments. The approach is novel in that it requires developers to make the spaces on which they are building as biodiverse, or ideally more biodiverse, following development — something that is perhaps hard to conceive when considering a building site. Although some developers have already adopted this concept, the Government is now planning to make it mandatory.
The new rules will mean that sites have to be assessed prior to development and a plan drawn up for how the development will be created to ensure it has a positive impact on biodiversity. If developers are unable to do this onsite, they must create compensatory habitat elsewhere — ideally locally. If this is not possible, a tariff will be levied to create habitat in another part of the country according to national priorities.
The new rules for developers were consulted on in late 2018 and early 2019. Following on from consultation, the Government announced in its Spring Statement that it would use the forthcoming Environment Bill to mandate the approach in England, and in March 2019 the Government confirmed that it was planning on making the net gain approach mandatory.
There is a rich diversity of studies showing that natural environments are crucial to human health, both physically and mentally. Growing evidence is confirming what we intuitively know: that nature is good for our health.
However, our love and need for nature is at odds with how we’re currently treating the planet. Population growth and increasing rates of consumption, spurred on in part by technological advancements, have caused species extinction rates to sky-rocket. A new emphasis on nature for health might go some way to slow this damage as by re-establishing a connection with the world around us, we will undoubtedly also take better steps to improve the environment that supports us.
The interactions and relationships between us and nature are complex, and in many cases the exact mechanisms by which benefits occur are not fully understood. However, while public policy and modern medicine catches up, you can take matters into your own hands by simply getting outside, enjoying your nearest park or forest and perhaps bringing the outside in by buying a few more pot plants. By doing so you’ll undoubtedly make a world of difference to both you, and the planet.
Last reviewed 2 July 2019