I spend a few months each year in Ho Chi Minh City, based around District 7, and between work blocks I have a route that takes longer than it needs to. There’s a riverside stretch, then a cut-through park. The light comes off the water in a way I keep coming back to, and there are people everywhere just living their lives, fishing, sitting, getting on with the day. In the moment it doesn’t feel like much. But I notice, again and again, that I come back to my work more focused and in a better mood than the day seems to justify.
I never thought of it as anything more than a nice walk. Then I came across a study that put a name to the thing I’d half-noticed, and a number on it.
A quick flag before I go further: I’m a writer, not a psychologist, and nothing here is advice about your mental health. This is a single snapshot study. It shows that two things tend to go together, not that one causes the other, and it covers particular groups of people in particular cities. Read it as a curious person reading research, not as a prescription. And if any of this is sitting closer to home than it is interesting, a qualified therapist is worth far more than a blog post.
What the four-city study actually found
The paper is by Wilma Zijlema, Mark Nieuwenhuijsen and colleagues, published in 2018 in Environment International. They looked at survey answers from 3,599 adults across four cities in Europe. People reported how they got to work and how they were doing.
The “natural environments” in the study weren’t just parks. The paper’s own definition covered green things like street trees and forests, and blue things like canals, rivers and ponds. My riverside-and-park route would have ticked both boxes, as it happens.
People who commuted daily through these surroundings scored, on average, 2.74 points higher on mental health than people who passed through them less often. As Zijlema put it, “our data show that commuting through these natural spaces alone may also have a positive effect on mental health.” The hedge in her own words, “may,” matters. This is a link, not a proven cause.
The combination is the interesting bit
The benefit was strongest for the people who walked or cycled through the green and blue surroundings. Active commuting on its own, without the natural surroundings, was not linked to better mental health at all. It wasn’t the movement on its own or the scenery on its own that did the work; it was the two together.
That tracks with my own messy, unscientific experience. My Dublin commute on foot and by bike was greyer, and I never felt the lift I got from the District 7 route. I’m not going to pretend that’s clean evidence. Vietnam is a lot sunnier than Ireland, and sunshine alone could explain a chunk of the difference. City life there feels more lived-in too. The green-inside-a-dense-city version helped, but it was never the same as being out in the countryside.
Zijlema is careful about how far any of this reaches. “Although this study is the first of its kind to our knowledge and, therefore, more research will be needed,” she said.
What I take from it, which isn’t a prescription
It’s worth keeping the size of the thing in proportion. A 2.74-point shift on a 100-point scale is real but modest. And a single snapshot can’t tell you whether the route lifted people’s mood or whether happier people simply chose nicer routes.
So I don’t take this as a rule to live by. Nieuwenhuijsen, the senior author, frames it as a question for the people who design cities, suggesting that “one way of doing so would be investing in natural commuting routes for cycling and walking.” Conditional language, “one way.” That’s the right register for it.
What I take from it is smaller and more personal. Where there’s a greener way to get somewhere on foot, and it doesn’t cost me much time, I’ll usually take it. The rest of the year I’m based in rural Ireland, where most of where I am is green anyway, so the greener route is usually just the route I’m already on. But when it is a choice, the District 7 mornings are enough to make me pick it.
