How Much Time in Nature Is Enough? About Two Hours a Week

Advice to get outside more is easy to agree with and hard to act on, because it rarely says how much. A study from the University of Exeter, published in 2019, is one of the few that tried to put a figure on it. The figure is smaller than most people would guess: about two hours a week, and it doesn’t have to come all at once.

Two hours is a Saturday morning in a park and a couple of lunch breaks spent somewhere with trees. You don’t need hiking boots or a drive into the hills.

Where the Two Hours Come From

The Exeter team used a national survey of about 20,000 people in England, who were asked how much time they had spent in natural settings over the previous seven days. Those who reported at least 120 minutes were significantly more likely to describe their health as good and their wellbeing as high than those who reported none. Below that, the difference wasn’t clear. The association levelled off at around 200 to 300 minutes a week, with no further gain beyond that.

It’s worth being clear about what this study can’t show. Everything was self-reported, it covered a single week, and it was observational. People who already feel well are more likely to go for walks in the first place, and the researchers couldn’t fully separate that from any effect of the walks themselves. Treat 120 minutes as a sensible target, not a proven cut-off.

White, M.P. et al. (2019). “Spending at least 120 minutes a week in nature is associated with good health and wellbeing.” Scientific Reports, 9, 7730.

The detail we find most useful is how the time was made up. It made no difference whether someone reached two hours in one long weekend walk or in several shorter visits during the week, which helps if your weekdays are full and a free afternoon is rare.

A Walk Away from the Traffic

A smaller experiment from Stanford gets closer to cause and effect. In 2015, Gregory Bratman and colleagues sent 38 healthy city dwellers on a 90-minute walk. They were randomly assigned to walk either through grassland with scattered oak trees or along a busy road. Before and after, each person filled in a questionnaire on rumination (going over the same negative thoughts again and again) and had a brain scan.

After the nature walk, people reported less rumination, and the scans showed reduced activity in the subgenual prefrontal cortex, a brain area linked to that kind of repetitive thinking. Those who walked beside the traffic showed no such change. Both groups walked for the same length of time, which points to the setting rather than the exercise.

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.

Thirty-eight people and a single walk is a small base, and the measurements were taken right afterwards, so the study says nothing about how long the effect lasts. It does match what a lot of people notice for themselves. It’s harder to keep replaying an argument with your manager when there’s a heron on the riverbank to look at.

What Shows Up in the Body

For physical measures, the widest view comes from a 2018 review at the University of East Anglia that pooled more than 140 studies of green space and health. More exposure to green space was associated with lower salivary cortisol (a stress hormone), a lower heart rate and lower diastolic blood pressure, the second number in a reading, as well as a lower incidence of type 2 diabetes. Most of those studies were observational, though. People who live near parks differ from those who don’t in income and plenty else, and many of the short-term cortisol and heart-rate readings came from Japanese research on forest bathing, where people walk slowly or sit among trees.

Twohig-Bennett, C. & Jones, A. (2018). “The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes.” Environmental Research, 166, 628-637.

Fitting Two Hours into an Ordinary Week

None of this research asks for anything dramatic. Spread over seven days, two hours is about 17 minutes a day, and many people already spend that long walking somewhere. Often the change is just the route. A path through the park instead of along the main road, a canal towpath, a street with trees on both sides, a stretch of river or seafront: none of it is wilderness, and most of it is the kind of place the Exeter survey counted.

Autumn is a good time to start, while the leaves are turning. An hour on a Saturday or Sunday morning somewhere with trees gets you halfway, and two or three shorter walks at lunch cover the rest. Leave the phone in your pocket if you can, since it’s hard to stop going over a problem while you’re reading about it. And if your mood has been low for more than a couple of weeks, keep the walks going but talk to a doctor as well.

If you want to see whether it makes a difference for you, Lamplit’s journal has a mood check-in that takes three taps: how you feel on a five-point scale, a more specific feeling, and the part of life it’s about. Do it after an outdoor walk, and on a few days you spend mostly indoors. Mentioning the walk in the “Today’s growth” prompt makes those days easy to find later, and after three or four weeks the mood trends in the journal’s analytics will show whether they look any different from the rest. You can also log the walk itself as a light workout. All of it is free.

Open your Lamplit journal after your next walk outside and do the mood check-in. It’s free.