Over the fence: our mental wellbeing

Is there enough scientific evidence to prove gardening is good for our health?

Fifteen years ago, we at the University of Essex set about creating an evidence base for the health benefits of activities in nature. We called this ‘green exercise’. Dozens of studies are clear: being active in the presence of nature improves mental and physical health, for all ages and social groups, and in all settings from gardens to farms and woods.

We later coined the term ‘a dose of nature’, a deliberately medical term to suggest that we can choose activities to improve well-being. We also found a positive effect of seeing green views from the window.

What is the explanation? We found that being attentive and immersed is a boost to the parasympathetic nervous system, which plays a key role in our immune systems. Being attentive is something we naturally do in a garden. Being immersed then also takes us away from the constant background mental chatter.

Another factor is that moving forward into landscapes, by walking or gardening, increases the volume of the brain’s hippocampus region – the centre for memory and learning. We now know being active in natural environments provides protection against the onset of some dementias. Thus the cognitive aspect of gardening – thinking, planning, acting – keeps the brain active for longer in life.

The Japanese seem to do five things daily to help them live long and well (there are many centenarians in Japan): they are active physically; eat largely plant- and sea-based foods; learn something every day; socially connect with friends and family and spend time in nature, either gardening at home or at temples.

The evidence is strong: nature is good for our health, and gardens, parks and reserves provide a perfect location for us to stay healthy, especially in these troubling times.

With levels of anxiety and depression on the rise, research into the health benefits of gardening has never been more important. There is strong scientific evidence for the anti-stress effects of green nature, through lowering heart rate and blood pressure and reducing levels of the stress hormone cortisol. But gardening is about more than spending time in nature – a garden is a creative and interactive environment. Neuroscientists refer to the benefits of different types of stimulating environment such as this as ‘enriched environment’ effects. Research on rats, whose brain structures are similar to ours, show the importance of enriched environments for brain health – rats become more resilient when exposed to stress, show greater persistence in tasks and interact with each other in a more lively way. In other words, they show signs of increased vitality, purpose and motivation.

Research findings on gardening show similar effects in people, particularly on raising self- esteem and helping alleviate depression and anxiety. But many of these studies are small and very few meet the strict criteria of a medical evidence base. With the growing interest in social prescribing and therapeutic gardening, it will be important to develop this. There is, however, one recent study that has achieved the rigours of a randomised controlled trial. The research was carried out in Denmark and published in the British Journal of Psychiatry in 2018. People suffering from stress disorders were randomly allocated to two treatments – either wellproven cognitive behavioural therapy or horticultural therapy. Both lasted 10 weeks and showed a similar level of benefit. Given that many of the therapeutic effects of gardening unfold over a longer period of time as the seasons progress and the plants grow, this is a striking result.

The cognitive aspect of gardening keeps the brain active for longer in life

Many of the studies are small and few meet the criteria of evidence base

How important do you feel scientific evidence is in proving the health benefits of gardening? Do you feel the benefits yourself? Email or write to us at the addresses on page 24