The feeling of seeing the lush green of nature, hearing the babbling blues of the rivers, and witnessing the immovable greens and browns of the mammoth trees and mountains is often a balm for the soul.
It’s a feeling easily missed, perhaps only noticed on the way back, in how your shoulders have dropped an inch without you deciding to relax them.
Long before anyone thought to measure it, this was just something people knew.
Now researchers have spent decades trying to work out what’s actually changing, and how much of it holds up to scrutiny. So let’s walk through what the evidence shows, why nature seems to have this effect, and how much of it you actually need.
What The Research Actually Found
One of the more physical pieces of evidence comes from measuring cortisol, the hormone your body releases under stress. Antonelli et al. (2019) pooled data from people who spent time in forests and compared them with people who spent similar time in cities, and found cortisol levels were reliably lower in the forest groups. Interestingly, cortisol was already lower in the forest groups before the walk even began, a detail the authors attribute partly to anticipation, the calming effect of simply expecting to be somewhere pleasant.
A small brain-imaging study of healthy volunteers adds a different kind of evidence. Bratman et al. (2015) had healthy adults take a 90-minute walk, either through a natural setting or along a busy urban street, then measured both their self-reported rumination (the looping, negative thinking that tends to accompany low mood) and activity in a brain region called the subgenual prefrontal cortex, which has been linked to depression risk. Only the nature walk reduced both.
The pattern largely holds at population scale, too. Liu et al. (2023) pooled observational studies and found that a 10% increase in local green space was associated with lower odds of depression, with greener neighbourhoods, measured by satellite imagery, tracking with lower depression odds as well. The link with anxiety was weaker. And because this evidence comes from people’s actual living situations rather than controlled experiments, it can’t rule out the possibility that people already doing better simply choose to live somewhere greener.
Taken individually, none of these findings would be impressive. Taken together, the data reliably points the same way. The most rigorous synthesis of trial evidence, a meta-analysis of 50 studies by Coventry et al. (2021), found that nature-based interventions meaningfully improved depressive mood and positive affect, with anxiety and negative affect also improving.
The overall shape of the evidence is more convincing than any single result could be alone.
Why It Might Work This Way
Two explanations dominate the science, and they answer slightly different questions.
The first, Attention Restoration Theory, was proposed by Kaplan (1995) and starts with a simple observation: focusing hard on anything — traffic, deadlines, a crowded inbox — draws on a limited mental resource he called “directed attention.” Use it too long and it tires, the same way a muscle does, leading to irritability, poor decisions, and a harder time concentrating.
Kaplan’s argument was that natural environments are unusually good at letting that resource recover, because they hold your attention gently rather than demanding it. A view of moving water or a canopy of leaves is interesting enough to notice, but not effortful enough to exhaust you — what Kaplan called “soft fascination.” You’re giving your attention a rest without asking it to do nothing at all.
The second explanation, Stress Reduction Theory, comes from Ulrich et al. (1991) and takes a more physiological route. Rather than attention, it centres on the body’s fast, largely automatic response to a setting that looks safe.
In Ulrich’s original experiment, people were stressed and then shown either natural or built environments; those looking at nature recovered faster and more completely, with their physiological measures approaching baseline within the first four minutes and showing a clear advantage over the urban group by five to seven minutes. The theory suggests this reaction is evolutionary: humans may simply be wired to relax at the sight of vegetation and water, before any conscious thought about the scene has time to form.
These two ideas are often treated as rivals, but they’re really describing different layers of the same event: the body calming quickly and without much thought, while the mind’s capacity to concentrate recovers more slowly in the background.
Researchers haven’t fully settled which does more of the work, and the honest answer is that nature-based programmes usually come bundled with other things, a walk means exercise, a group session means company, so untangling the effect of “nature” alone from these other, likely helpful, ingredients is genuinely difficult (Coventry et al., 2021).
How Much Time You Actually Need
In a study of nearly 20,000 English adults, people who spent at least 120 minutes in nature over the course of a week were significantly more likely to report good health and high wellbeing than those who spent no time in nature in that same duration (White et al., 2019). Below that threshold, the associations were weak; above it, they grew steadily before levelling off somewhere around 200 to 300 minutes, after which more time didn’t seem to add much further benefit.
What’s easy to miss is a more forgiving detail buried in the same study: it made no difference whether people reached those 120 minutes in one long outing or across several shorter ones spread through the week (White et al., 2019).
A Sunday afternoon walk counts. So do five short trips to the local park. This is a cross-sectional study, meaning it captures a single snapshot in time rather than following people over months or years, so it can’t fully rule out the possibility that healthier people simply choose to spend more time outdoors. Still, as a practical benchmark, it’s a useful and fairly attainable one.
Separately, in trials testing structured nature-based programmes rather than casual visits, the most effective programmes ran for 8 to 12 weeks, with individual sessions of 20 to 90 minutes (Coventry et al., 2021).
A Heads Up
None of this means that “just go outside” is a complete answer, especially if what you’re carrying is heavier than everyday stress. Advice that sounds simple can feel dismissive when someone is genuinely struggling, and nature exposure was never tested as a replacement for therapy, medication, or the support of people who know your situation.
There’s no single right way to bring more of nature into a life. Maybe a lunchtime walk, a windowsill of plants, or weekends spent somewhere greener than the supermarket.
The research suggests it’s certainly worth spending time in nature.
If time outdoors is something you’d like to build into a fuller picture of your mental wellbeing, alongside crucial professional help, we’re always just a call away!
References
- Antonelli, M., Barbieri, G., & Donelli, D. (2019). Effects of forest bathing (shinrin-yoku) on levels of cortisol as a stress biomarker: A systematic review and meta-analysis. International Journal of Biometeorology, 63(8), 1117–1134. https://doi.org/10.1007/s00484-019-01717-x
- Bratman, G. N., Hamilton, J. P., Hahn, K. S., Daily, G. C., & Gross, J. J. (2015). Nature experience reduces rumination and subgenual prefrontal cortex activation. Proceedings of the National Academy of Sciences, 112(28), 8567–8572. https://doi.org/10.1073/pnas.1510459112
- Coventry, P. A., Brown, J. V. E., Pervin, J., Brabyn, S., Pateman, R., Breedvelt, J., Gilbody, S., Stancliffe, R., McEachan, R., & White, P. C. L. (2021). Nature-based outdoor activities for mental and physical health: Systematic review and meta-analysis. SSM – Population Health, 16, 100934. https://doi.org/10.1016/j.ssmph.2021.100934
- Gascon, M., Zijlema, W., Vert, C., White, M. P., & Nieuwenhuijsen, M. J. (2017). Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies. International Journal of Hygiene and Environmental Health, 220(8), 1207–1221. https://doi.org/10.1016/j.ijheh.2017.08.004
- Kaplan, S. (1995). The restorative benefits of nature: Toward an integrative framework. Journal of Environmental Psychology, 15(3), 169–182. https://doi.org/10.1016/0272-4944(95)90001-2
- Kotera, Y., Richardson, M., & Sheffield, D. (2022). Effects of shinrin-yoku (forest bathing) and nature therapy on mental health: A systematic review and meta-analysis. International Journal of Mental Health and Addiction, 20(1), 337–361. https://doi.org/10.1007/s11469-020-00363-4
- Liu, Z., Chen, X., Cui, H., Ma, Y., Gao, N., Li, X., Meng, X., Lin, H., Abudou, H., Guo, L., & Liu, Q. (2023). Green space exposure on depression and anxiety outcomes: A meta-analysis. Environmental Research, 231(Pt 3), 116303. https://doi.org/10.1016/j.envres.2023.116303
- Roberts, H., van Lissa, C., Hagedoorn, P., Kellar, I., & Helbich, M. (2019). The effect of short-term exposure to the natural environment on depressive mood: A systematic review and meta-analysis. Environmental Research, 177, 108606. https://doi.org/10.1016/j.envres.2019.108606
- Ulrich, R. S., Simons, R. F., Losito, B. D., Fiorito, E., Miles, M. A., & Zelson, M. (1991). Stress recovery during exposure to natural and urban environments. Journal of Environmental Psychology, 11(3), 201–230. https://doi.org/10.1016/S0272-4944(05)80184-7
- White, M. P., Alcock, I., Grellier, J., Wheeler, B. W., Hartig, T., Warber, S. L., Bone, A., Depledge, M. H., & Fleming, L. E. (2019). Spending at least 120 minutes a week in nature is associated with good health and wellbeing. Scientific Reports, 9, 7730. https://doi.org/10.1038/s41598-019-44097-3