On the basis of an analysis of nearly 20,000 people’s feedback, a recent paper concluded that just two hours of outdoor recreation per week is sufficient to yield a significant improvement in health or well-being, compared to people who get no recreation time in green spaces at all. In fact, the more time people spent engaged in outdoor recreational activities, the more happy or healthy they reported to be; an effect that peaks somewhere between 200-300 mins of weekly exposure to mother nature.
Many previous papers have reached similar conclusions. A meta-analysis of 21 studies suggested that a person’s chances of developing a mood disorder were increased by 28% if they lived in urban as opposed to rural areas, where nature is more easily accessed. There are of course other possible explanations for urban dwellers being more likely to encounter mental health issues than rural ones. Perhaps humans are just more vulnerable to such disorders in a densely as opposed to sparsely populate environment? Or is it really something to do with the presence of trees in the environment?
This possibility has been addressed by studies using high-resolution satellite imagery to plot tree density against various measures of well being in a huge sprawling urban area in Toronto, Canada. One such study (by Kardan et al, 2015) concluded that people who lived in an area with a higher density of trees in their neighbourhood had a significantly higher perceived health level and a lower incidence of cardio-vascular conditions.
This complements the earlier study mentioned above that compared the mental health outcomes of people who moved from more green to less green urban areas and vice versa. Alcock and colleagues analysed 5 consecutive years worth of data from 1,084 British households, finding that those who moved from less green to more green urban areas enjoyed fewer mental health complications over the following three years.
In a previous blog I described the classic study of patients who were recovering from a straightforward hernia operation in adjacent rooms, one that had a view of a brick wall and one that had a view of a small patch of grass with a tree growing in it. The patients who ended up in the room with the view of the tree recovered faster (as evidenced by the number of days they stayed in hospital post-surgery) and even required lower doses of analgesic medication to help them cope with the pain. Other studies have gone on to suggest that just being able to look out the window to catch sight of a slice of mother nature reduces aggression and criminal activity.
So what is is about plants and trees that seems to have such a profound impact on how we feel? Hartig et al (2016) suggest that viewing a natural scene helps us to put things in perspective, to create a healthy psychological distance between the day-to-day grind by actively engaging our attention in features of the natural landscape. This can help us to repeatedly gain the positive and reinforcing experience of feeling our mood lift and stress subside, both of which naturally occur when we turn our back on the hectic urban world and engage with the more relaxed pace typical of open green spaces. Beyond these important factors, trees also improve air quality and aesthetic appearance of an environment.
Across many studies, having access to green spaces has been shown to promote mental health, reduce accidental death and even mitigate against the negative impact of economic struggles on various health measure. It also reduces blood pressure and stress by promoting physical activity and reducing sedentary leisure time.
Even before I read all about this body of research attesting to the physical and mental health benefits of spending leisure time in natural settings, my behaviour over the last few years suggests that I knew this innately. Since I moved into my flat a few years back I’ve spent countless hours watching our neighbourhood sparrows, blackbirds, blue tits, goldfinches, crows and wood pigeons flitting around the communal gardens (see above) that I can see from my balcony. When I taking breaks from researching and writing books and blogs while surveying this green scene, I can feel the stress drain out of my body. Then when I get back to work, I feel significantly better able to crack on after the ten to fifteen minutes spent watching the natural world do its thing; an observation supported by research indicating that attention and memory resources get a boost from even a brief exposure to nature.
Beyond engaging with mother nature as a spectator, one of my favourite recreational past-times is to go running around Richmond Park with my mate Nathan. We’ve been doing it once a month for the past eight years. We talk almost non-stop during these 10km runs, mostly about nonsense just to reduce our perceived exertion (i.e. to distract ourselves from the bodily discomforts of keeping up a brisk jog for a solid hour), but we also regularly find ourselves commenting on how life just seems much better, easier, less daunting when you get outside, running cross-country through woods, fields of fern and grassy plains studded with herds of deer. It seems that the academic research data supports these views and backs the idea that communities benefit hugely from improved access to green spaces.
In addition to these monthly brain blogs, I regularly tweet about the latest neuroscience research to hit the lay press and review a virtual reality game or experience every week on my YouTube channel Brain Man VR.