Nature

120 minutes in nature a week: the threshold and the ceiling

Yes, 120 minutes a week is the point at which the association with health appears. In a 2019 study of 19,806 adults in England, people who had spent 120 to 179 minutes in parks, woodland, countryside or on the coast during the previous 7 days had 1.59 times the odds of reporting good health and 1.23 times the odds of high wellbeing compared with people who had spent none, after adjusting for 15 other factors. Below 120 minutes the difference was not significant, the gains flattened at about 200 to 300 minutes, and one long visit or several short ones made no difference.

What the survey measured

The figure comes from the Monitor of Engagement with the Natural Environment survey, an in-home interview survey run across England. Mathew White and colleagues at the University of Exeter took the 2014/15 and 2015/16 survey years, weighted the sample to match the national population, and analysed the 19,806 respondents with complete data. Each person listed their recreational visits to the outdoors for each of the previous 7 days, then gave the length of one visit chosen at random. Visit length multiplied by visit count gave weekly minutes, sorted into 60-minute blocks.

The outdoors was defined broadly: parks, canals and nature areas in and around towns; the coast and beaches; farmland, woodland, hills and rivers. Shopping trips and your own garden did not count. Health was one question, how is your health in general, with good or very good counted as good (76.5 percent of the weighted sample). Wellbeing was the UK life satisfaction question scored from 0 to 10, with 8 to 10 counted as high (60.2 percent). One number stands out before any statistics: 11,668 of the 19,806 people, about 59 percent, had spent no recreational time in nature in the previous week, while 3,484 had spent 300 minutes or more.

The threshold at 120 minutes and the ceiling near 300

Before any adjustment, the weighted share reporting good health rose from 72.3 percent at 0 minutes to 74.8 percent at 1 to 59 minutes, 80.3 percent at 60 to 119 and 84.5 percent at 120 to 179, then moved between 81.9 and 84.5 percent. High wellbeing followed the same curve: 57.2 percent at 0 minutes, 64.7 percent at 120 to 179, and 64.0 to 65.9 percent above that.

Those shares mislead, because people who visit nature also tend to be younger, better off and more active. The authors adjusted for 15 factors, from green space around the home and area deprivation to age, social grade, physical activity and long-term illness. With those controls, 1 to 59 minutes gave an odds ratio for good health of 1.04 and 60 to 119 minutes gave 1.13, neither significant. At 120 to 179 minutes the ratio was 1.59 (95 percent confidence interval 1.31 to 1.92) and the wellbeing ratio 1.23 (1.08 to 1.40). Higher bands kept the association without extending it: 1.44 at 180 to 239 minutes, 1.55 at 240 to 299 and 1.33 at 300 or more. Modelling minutes as a continuous curve showed diminishing returns beyond 120 minutes and a flattening, or slight fall, at about 200 to 300 minutes, with intervals too wide to read anything above 400.

One caution about the number itself: 78 percent of the answers in the 120 to 179 band were exactly 120 minutes, because people recall visits in round figures, which is why the study worked in whole hours. Read the threshold as about 2 hours; the authors call both the threshold and the peak starting points for further research rather than settled findings.

One long visit or several short ones

The study tested this directly: the association at 120 minutes or more was the same whether the time came from one long outing or several shorter ones, and the authors warn against telling either kind of visitor to switch. The patterns compared were one visit of 120 minutes or more, two of 60 minutes or more, and three or more of 40 minutes or less, and they came out the same. In the research centre's announcement, the lead author called 2 hours a realistic target for many people precisely because it can be spread over the whole week, and most of the recorded visits took place within 2 miles of home.

A small physiological study points the same way for short visits. In 2019, 36 urban residents (mean age 45.8, 92 percent women) were asked to spend at least 10 minutes in a place that gave them a sense of contact with nature, at least 3 times a week for 8 weeks, collecting saliva before and after a visit on 4 occasions. Salivary cortisol fell by 21.3 percent an hour during a visit, on top of its usual 11.7 percent hourly decline through the day, and the return per minute was greatest between 20 and 30 minutes, after which the benefit continued at a slower rate. That is 1 study of 36 self-selected volunteers without a control group, so treat it as a plausible mechanism rather than proof.

Who the pattern held for

The threshold was not a feature of one comfortable group. When the sample was split, the odds of good health with 120 minutes or more, compared with none, were 1.28 among the 14,667 adults aged 16 to 64 and 1.87 among the 5,193 aged 65 and over. They were 1.42 both for the 4,545 people with a long-term illness or disability that limited their daily activities and for the 15,261 without, a sign, the authors argue, that this is not simply healthy people going out more. It held in urban areas (18,694 people, odds ratio 1.38) and rural ones (1,112 people, 2.27), in deprived and affluent areas, in both sexes and across social grades. It held for the 15,008 people who missed the 150-minute activity guideline (1.48) and, more weakly, for the 4,798 who met it (1.22), so time in nature is not just exercise under another name. The one exception was the 4,608 respondents who were not White British, whose health ratio of 1.21 did not reach significance, although their wellbeing ratio of 1.22 did.

To give the association a scale, the authors set it beside other predictors in the same model. For health, 120 to 179 minutes a week versus none was worth about as much as living in a low rather than high deprivation area, meeting rather than missing the activity guideline, or being in a higher rather than lower occupational grade. For wellbeing it matched green space, deprivation and activity, but counted for less than social grade and relationship status.

What the evidence cannot tell you, and how to use it

The study is cross-sectional: everyone was asked once, about the previous week. It shows that the groups differ, not that nature caused the difference, and the authors say plainly that healthier people may simply go outdoors more. Visit lengths were self-reported, which is less accurate than location tracking. Time in nature explained only about 1 percent of the variation in health or wellbeing in the unadjusted models: a modest, consistent association, not a large one. The setting was England, so the numbers may not transfer to a very different climate.

The direction fits the wider evidence. A 2018 systematic review from the University of East Anglia pooled 143 studies with more than 290 million participants and found that greater green space exposure went with lower salivary cortisol, a heart rate lower by 2.57 beats a minute, diastolic blood pressure lower by 1.97 mmHg, and lower risk of type 2 diabetes (0.72), cardiovascular death (0.84) and death from any cause (0.69), while warning of poor study quality and high heterogeneity in many pooled results. Most of those studies measured green space near the home rather than minutes spent in it, the gap the 2019 survey set out to fill.

In practice, 120 minutes a week sits beside, not inside, the World Health Organization's call for at least 150 minutes of moderate activity a week, a level that 31 percent of adults worldwide (1.8 billion people) do not reach. The two overlap: a brisk 30-minute walk in a park on 4 days covers 120 minutes of nature and most of the activity target. If you have heart disease, take medication that makes your skin sensitive to sunlight, are pregnant in hot weather or have a condition that limits walking, remember that the survey counted time, not effort: a bench by the water counts, and it is the exertion, not the nature, to discuss with your doctor. The Nature Dose Planner spreads 120 minutes across your week, and the guides on daily steps and sitting time cover the questions on either side.

Ways to reach 120 minutes

Frequently asked

Does a city park count?

Yes. The survey defined the outdoors as open spaces in and around towns and cities, including parks, canals and nature areas, as well as the coast, beaches and countryside. Most recorded visits took place within 2 miles of home, and the 120-minute pattern held in urban areas, with an odds ratio of 1.38 among 18,694 city residents.

Does time in my garden count?

Not in this study. The survey excluded time in your own garden and routine shopping trips, so the 120 minutes refers to visits to public green or blue space. The authors note that gardens can be a meaningful form of nature contact, but they had no data on it.

Is more than 120 minutes better?

Only up to a point. The odds of good health were 1.59 at 120 to 179 minutes, 1.44 at 180 to 239, 1.55 at 240 to 299 and 1.33 at 300 minutes or more, and a continuous model showed the curve flattening at about 200 to 300 minutes. More time was not harmful; it simply added little on this measure.

Do I have to exercise while I am there?

No. The survey counted minutes, not effort, and the 120-minute threshold held among the 15,008 people who did not meet the 150-minute physical activity guideline, with an odds ratio of 1.48. Combining the two, for example a brisk 30-minute walk in a park on 4 days, is efficient but not required.

Can I split the 120 minutes into short visits?

Yes. The study found the association was the same whether 120 minutes came from one long visit or several shorter ones. In a separate 8-week study of 36 urban residents, cortisol fell fastest during the 20 to 30 minute window of a visit, so a run of short visits is a reasonable way to reach the total.

Does the study prove that nature makes you healthier?

No. It is cross-sectional and self-reported, so it shows an association at one point in time, and healthier people may simply go outdoors more. The threshold held among the 4,545 people with a long-term illness, which argues against that explanation without ruling it out, and the authors call for longitudinal and intervention studies.

Sources

• White et al. 2019, Scientific Reports: Spending at least 120 minutes a week in nature is associated with good health and wellbeing · 19,806 adults from the Monitor of Engagement with the Natural Environment survey, England, 2014 to 2016; open access, tables 1 to 3 give the figures quoted
• University of Exeter, European Centre for Environment and Human Health: Two hour nature dose boosts health and wellbeing · Research centre announcement of 13 June 2019 with the lead author's comments; most visits within 2 miles of home; funded by the NIHR
• Twohig-Bennett and Jones 2018, Environmental Research: The health benefits of the great outdoors, a systematic review and meta-analysis of greenspace exposure and health outcomes · 143 studies, more than 290 million participants; full text on PubMed Central
• Hunter, Gillespie and Chen 2019, Frontiers in Psychology: Urban nature experiences reduce stress in the context of daily life based on salivary biomarkers · 36 participants over 8 weeks; cortisol fell 21.3 percent an hour during a nature visit; full text on PubMed Central
• World Health Organization: Physical activity fact sheet · Fact sheet of 26 June 2024; at least 150 minutes of moderate activity a week; 31 percent of adults, 1.8 billion people, do not reach it

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