“This windowless, stuffy room under the earth is actually my worst nightmare”, Professor Ward-Thompson starts off the first talk of the night. And she is right, the room is sweaty – the event is sold out and people are getting cosy, eager to see the screen. We soon find out why Prof. Catharine Ward-Thompson from the Edinburgh School of Landscape and Architecture made this remark. Her research focuses on the benefits of green spaces on health in the general public: physical, but also – and more importantly for this neuroscience-related night – mental health.
She explains that she initially she got a lot of resistance against her research. “You needed how much money and time to find out a walk in the park is good for you?”. But this work is not straightforward, and while she still cannot pinpoint the exact effects of nature and green spaces on our health, Prof. Ward-Thompson’s work offers some clues: apart from the beneficial effect of sunlight producing vitamin D in our skin, spending time in green spaces usually is connected with physical activity and acts on our HPA (hypothalamic-pituitary-adrenal) stress hormone axis. It relieves stress in a way that physical activity in the gym does not (an argument for moving your workouts outside if the rainy Scottish weather permits!). Secondly, fresh air contains many compounds beneficial to our health, including plant-derived volatine compounds such as phytoncides that may improve immunity, lower blood sugar and increase concentration. And third, public green spaces have an equigenic effect on different socio-economic backgrounds – creating more equality by allowing everyone to spend time in parks and not just those who can afford a big garden. Prof. Ward-Thompson’s newest work sends out people carrying mobile EEG machines on their heads, measuring brain waves while walking around the city. Preliminary data show that as soon as 5 minutes after entering a green space, the brain waves calm. Ideally, we should always be within 5-10 minutes’ walk of a park. Prof. Ward-Thompson has been pitching her work to the World Health Organisation to include this research in future city planning.
After a short break with a pub quiz for prizes to be won, the host, Dr Morrisson from the University’s chemistry institute, introduces the second speaker for the night: Dr Paula Brunton. Her talk ties into the overarching theme of how our environments determine our health. Dr Brunton’s fascinating work, carried out at the Roslin Institute, looks into how maternal stress during pregnancy leads to more anxious and depressive behaviours in the next generation. The data she shows is based on studies in rats, but the same holds true for humans. Evidence for this stems from cohort studies after catastrophes such as Hurricane Katrina or 9/11 (after all, it doesn’t seem very ethical to stress pregnant women for research).
Interestingly, acute stress can be tolerated relatively well by developing organisms – the placenta expresses an enzyme that can degrade cortisol, the stress hormone, leading to a buffer system. However, if cortisol is chronically elevated, this enzyme can’t do its job properly anymore and the stress hormone can accumulate in the fetus. This leads to a variety of effects, most strikingly more anxiety, depression and schizophrenia in the offspring.
How does this make sense? The most likely answer lies in evolution – the maternal body wants to let the offspring know about the environment it will be born into. If this is a stressful environment, the offspring needs to be more alert: imagine a mother field mouse being hunted for prey – her baby mice would need to be more alert and anxious in order to survive. However, if there is a mismatch between the environment implied by the stress hormone and the actual world the offspring is born into, this might pose a problem: a more alert and hyperactive system may cause anxiety, depression and in most severe cases schizophrenia. In our current, stressful world, this mechanism is not ideal – but evolution may simply not have caught up with it yet.
As I step into the fresh evening air of Edinburgh after the event, I consciously decide to take a walk home through the park instead of taking a bus – for the sake of my mental health.
This article was written by Chiara Herzog and edited by Bonnie Nicholson.
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