Gardeners know it, and the research evidence is convincing: gardening is good for you in so many ways. A 2003 Dutch study showed that for every ten per cent increase in regular exposure to gardens or green space, there is a health improvement equivalent to being five years younger. I can’t think of any drug that could make such a claim, and if there were such a thing, people would be queuing up to take it.
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More than half the UK population are gardeners, and this figure rises as we get older, so it follows that gardening can therefore be beneficial to the health of our ageing population. But we don’t need to wait until we’re a certain age: school garden projects have shown an impact that can lay the foundations for a healthy life.
Fit, strong and happy
Many studies have shown that gardeners are more physically active than non-gardeners, and a 2018 systematic review confirmed that gardening causes falls in blood pressure, heart rate and body mass index, which protect us from stroke, cardiovascular diseases, obesity, cancers and other diseases.
So how do these benefits actually work? Let’s start with the bones: gardening can maintain mobility, and physical exercise is known to enhance bone density and protect against osteoporosis. Stronger bones mean fewer fractures, and bones are also protected by the healthier levels of vitamin D seen in gardeners. This is metabolised into its active form by sun exposure on the skin. And vitamin D has other benefits: reduced levels make us feel low in mood and fatigued – indeed weakness of the muscles is a symptom of vitamin D deficiency.
Muscle strength is further helped by the act of gardening. This is especially beneficial if you have arthritis or other joint problems. In addition, gardening improves cardiorespiratory fitness and burns calories: between 250 and 350 for each hour in the garden. Three hours of gentle work in the garden equates to a hard hour in the gym (and I really hate the gym).
All the while our adrenal glands produce less cortisol – the stress hormone – and endorphins released during exercise give us a buzz too. More gardening could give us much more to be happy about – the Department of Health calculates that a ten per cent increase in average exercise by adults would avoid 6,000 premature deaths and save the NHS £500 million annually.
Boosting our defences
Our immune systems benefit from gardening too, in ways we’re only just beginning to comprehend. Cortisol is also an immune suppressant, so less of this helps, and the microbiology of the soil affects our gut health and immune wellbeing. This was originally demonstrated after shinrin-yoku (forest bathing) sessions in Japan, and the effects can be seen in blood tests for several weeks afterwards. These effects were reproduced in Finnish kindergarten children whose playground was filled with forest soil and peaty play areas. Subsequently, there was a big jump in the diversity of the children’s skin and gut bacteria, and they had markedly higher levels of protective white blood cells and interleukins, which play an important role in immune responses.
The theory is that broader biodiversity of our own skin and gut biome, and the resulting enhanced immune functioning, protect us from immune-modulated diseases such as asthma, allergies, rheumatoid arthritis and Type 1 diabetes. It can also improve our response to infections and our internal ability to detect and destroy early cancers. Conversely, the trend for ‘cleaner’ environments may explain the rising levels of many of these kinds of illnesses.
A feast for the senses
The way we engage with gardens through our senses of sight, sound, smell, taste and touch can profoundly affect our physiology. Green is the colour the human eye finds easiest to see. It sits in the middle of the visible spectrum where our perception is at its best. In psychological tests, functional MRIs and real-life assessments, controlling background colours has repeatedly shown green to make us more relaxed, more creative and more positive in our mood. It changes our brainwave activity and reduces blood pressure, pulse rate and muscle tension.
The soundscape in the garden plays a role too. Birdsong has been shown to be our preferred ambient sound, improving cognitive performance and physiological wellbeing, as well as reducing perceived pain. And for our noses there’s an aromatherapy cocktail out there, with botanical aromatics, such as terpenes (which include the scents of rosemary, pine, citrus, lavender and rose), and soil-based chemicals, such as geosmin, enhancing our physiological and psychological wellbeing. They reduce adrenaline levels, increase white blood cells and boost brainwave activity.
Toxin trappers
We know that living close to a busy road is linked to an increased risk of death from asthma, as well as increased rates and severity of dementia and cardiovascular disease. Gardens help filter the air pollution that can worsen these diseases. Trees, for instance, remove large quantities of toxins through their foliage, trapping them in leaves that later fall to the ground, where soil microorganisms break them down. It’s been estimated that, worldwide, forests offset a quarter of man-made carbon dioxide.
And in our own gardens, trees, hedges and other plants can reduce noise, heat, wind, flooding and soil erosion. Even lawns are helpful, trapping pollutants and passing them on to soil microorganisms, as well as providing recreational space for exercise.
It’s clear that there are a multitude of benefits to our physical health and wellbeing that come from gardening – so what are you waiting for? Fortunately, both for society as a whole and for the 87 per cent of us lucky enough to have access to our own outdoor space, the solution to many of our health problems is just there, outside the window, in the garden.
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