So what have parks, pets and windows got in common? A lot more than you might think, as we shall see. Let’s start with the room with a view. A study in California suggests that the more daylight a school captures, the more attendance increases, test results improve and learning rates are enhanced. And in hospitals too, windows have significant benefits, as research has shown. Recovery rates in wards that have views of trees were faster than those that looked out onto blank walls, and the tree-viewers also needed fewer analgesic doses and had lower scores for post-surgical complications. As for offices, if you are lucky enough to have a window with a tree-view, your recovery rate from low-stress events would be better than those unfortunates in windowless rooms.
Clearly there are genuine health benefits to be enjoyed, merely by observing trees. But is our ‘biophilia', our deep connection with the natural world, any more than helping us feel good, a ‘psychological uplift’? Here the answer is a profound yes: we don’t just like parks and gardens, we actually need them. Actively exercising in parks and working in gardens and allotments links us directly to our ancient hunter-gather past, firstly with our need for vitamin D and secondly for our immune system.
Let’s look at our deep history. We humans have been evolving for six million years, becoming ‘hunter-gatherers’, actively living off the land and building a working relationship with nature. That’s what we were (and still are) biologically-designed for. In spite of dramatic cultural and technological changes, our bodies remain broadly ‘Stone Age’, much as we were before towns or large-scale farming developed around 5,000-10,000 years ago.
And the active lives of our hunter-gatherer ancestors were spent outdoors, so different from the far more sedentary indoor lives most modern urban societies enjoy. Being continually in the open air was how our hunter-gatherer ancestors maintained their vitamin D levels. This essential vitamin helps us absorb minerals like calcium, iron, magnesium, phosphate and zinc. Since few foods contain vitamin D, sunlight is practically the only natural way to obtain this crucial benefit. Without it, osteomalacia (or rickets) occurs in children, while a deficiency in pregnant women can have tragic consequences for the newborn. Regardless of how sophisticated we have become, our uncivilised genes still expect us to be outdoors, topping up our vitamin D levels. Nowadays, being in parks and gardens helps us do this.
But there’s another reason why parks and gardens keeps us healthy. Our immune system works through the actions of tiny organisms that live on our skin and in the gut. Without them our susceptibility to allergies, autoimmunity and inflammatory bowel disease increases. The problem is that we’re not born with them: they’re derived from the mother’s birth canal and subsequently from various external sources, but especially from soil, plants, animals and fresh air. This unique but personalised ecosystem gradually co-evolved with us during the many millennia we were hunter-gatherers.
Living in towns, however, increases the risk of infections but limits our exposure to the helpful micro-organisms in nature. Since we still need physical contact with plants, trees, soil and animals to stay healthy, towns need parks, city farms, greened streets and sportsfields to support effective immune systems. Again, actively walking in parks or working in gardens, vegetables patches and allotments can prevent you falling ill.
Professor Graham Rook, whose research has done so much to help us understand our precious immune systems, makes particular mention of pets. He has observed that the beneficial microbiota from households with dogs is significantly richer than that found in homes without outdoor-loving pets. Consequently, the exposure of children to dogs, for example, can provide protection against allergic disorders. This seems to be because humans have co-evolved with canines and their friendly microbiota ever since the domestication of the dog. Our bodies have long been familiar with them, for at least the last 30,000 years. So, when your dog takes you for your daily walk in the park, you are not only exercising in the open air, but you’re also supporting your immune system.
The more we understand and respect our ancient biology, the healthier we will be. Our inner hunter-gatherer’s uncivilised digestive system requires a mixed and varied diet of fresh foodstuffs each day (not over-processed, over sugared industrialised products). Our uncivilised lungs need fresh air (not diesel particulates) and our uncivilised bodies need daily exercise. Furthermore, we have retained our Palaeolithic need for nature - especially in the middle of a town. And that’s where parks, pets and windows come in…
Gustav Milne is leading archaeologist and academic specialising in urban archaeology. He is the author of Uncivilised Genes – Human Evolution and the Urban Paradox. Available now on Amazon.