How Much Time Outside Do You Actually Need? (The 120-Minute Rule)

If you’re asking how much time outside per day you need, here’s the number: about 17 minutes. That’s what the best-known study on the question works out to when you spread its weekly target across seven days.

The actual finding is 120 minutes a week in nature. People who hit that mark were more likely to report good health and high wellbeing than people who got none. And it didn’t matter how they got there. Seventeen minutes a day works. So does two hours on Saturday.

Nobody publishes an official daily requirement for fresh air. But this is as close to one as the evidence gets, so it’s worth knowing exactly what it says.

Where the 120-minute rule comes from

The number comes from a 2019 paper in Scientific Reports led by Mathew White at the University of Exeter. His team used answers from 19,806 people in England who took part in a national survey about time in the natural environment. Each person reported how long they’d spent in nature in the past week, and rated their own health and wellbeing.

The result: compared with people who had no nature contact, people at 120 minutes or more were significantly more likely to report good health and high wellbeing. In the 120 to 179 minute group, the odds of reporting good health were about 59% higher, and the odds of reporting high wellbeing were about 23% higher. (Those are odds ratios of 1.59 and 1.23. “Higher odds” isn’t the same as “59% healthier”, so don’t put that on a mug.)

120minutes a week

Two more things made this study stick.

How you split it didn’t matter. One long visit or several short ones, the result was the same. As White put it when the study came out: “Two hours a week is hopefully a realistic target for many people, especially given that it can be spread over an entire week to get the benefit.”

It held across groups. The pattern was consistent for older adults and for people with long-term health issues, not just the young and fit.

How much time outside per day that works out to

120 divided by 7 is 17.1. Call it 17 minutes a day. But you don’t have to go every day, so here’s the same 120 minutes cut a few ways.

Days you get out	Minutes each time
7 days a week	17
5 days (weekdays)	24
4 days	30
3 days	40
2 days (the weekend)	60
1 day	120

Every row adds up to 120. Pick the one that matches your actual week, not the one that matches the person you plan to become in January.

Over a year, 120 minutes a week is 104 hours. That’s a little over four full days outside. It sounds like a lot more than “17 minutes”, which is sort of the point of doing small things daily.

Is more time outside better?

Up to a point, yes. In the study, the link with health and wellbeing kept strengthening past 120 minutes and peaked somewhere between 200 and 300 minutes a week. After that, no further gain.

In daily terms, 200 to 300 minutes a week is about 29 to 43 minutes a day. So the useful range looks like this:

• Under 120 minutes a week: in this study, not measurably different from zero.
• 120 minutes a week (about 17 a day): where the link shows up.
• 200 to 300 minutes a week (about 30 to 45 a day): where it tops out.

If you’re already doing an hour a day, great. You’re not getting triple the benefit by this study’s measure, but you’re presumably enjoying yourself, which was never something a survey could cap.

What if you can only manage 10 minutes?

Then do 10 minutes.

Here’s the honest version. Ten minutes a day is 70 minutes a week, and in the Exeter study people between 1 and 119 minutes were no more likely to report good health or high wellbeing than people at zero. That’s a real finding and we’re not going to wave it away.

But that study measured one thing: how people rated their overall health and wellbeing in a survey. A different 2019 study in Frontiers in Psychology measured the stress hormone cortisol in 36 people over eight weeks. It found that a single nature session was linked to a drop in cortisol, and that 20 to 30 minutes was the most efficient length. It’s a small study, and the authors say they didn’t have enough data to say much about sessions under 10 minutes. Still, it suggests a short session does something in the moment, even if it doesn’t move a weekly survey score on its own.

The practical answer: 10 minutes on weekdays is 50 minutes. Add one 70-minute outing on the weekend and you’re at 120. Short and daily builds the habit. One longer trip tops up the total.

What counts as “outside”?

The 120-minute study was about time in nature, meaning green and natural places people went to. It specifically excluded time spent in your own garden. So the number describes outings to what the researchers called natural settings: town parks, woodlands, country parks and beaches.

That leaves some obvious questions the study can’t answer. Does a tree-lined street count? Your porch? The cortisol study took a looser line: a nature experience was anywhere outside that, in the participant’s opinion, had enough natural elements. Which is a scientific way of saying “you’ll know it when you’re in it.”

A sensible reading:

• A park, a trail, a waterfront, a cemetery with old trees: yes.
• A walk through a leafy neighborhood: close enough. Go.
• Your backyard: outside, and better than the couch, but not what the 120-minute number was built on.
• The walk from the car to the office: no. Nice try.

Time outside is not the same as exercise

These get mixed up, so to be clear: the 120 minutes is about being in nature, not about breaking a sweat. Sitting on a bench counts.

Exercise has its own number. The CDC says adults need 150 minutes of moderate-intensity physical activity a week, which it notes can be 30 minutes a day, 5 days a week.

You can stack them. A 30-minute walk in a park, five days a week, is 150 minutes outside. If the pace is brisk enough to count as moderate activity, it’s also your 150 minutes of exercise. Two targets, one walk, no gym membership.

The fine print

This is a good study with honest limits, and the authors list them.

• It’s a snapshot. The data is observational and cross-sectional. People were surveyed once, not followed over time or assigned to go outside.
• It’s self-reported. People estimated their own minutes and rated their own health.
• The arrow could point either way. The authors say they can’t rule out that the link is partly because healthier, happier people spend more time in nature.
• It’s England. Different weather, different parks, different people. The number may not transfer perfectly.

So 120 minutes is a well-supported target, not a prescription. Nobody has shown that going from 0 to 120 will cause you to feel better. What the study shows is that the people who do it tend to be doing better. Given that the cost is a walk, that’s a bet most people can afford.

And it isn’t medical advice. If you’re dealing with something serious, a park is a nice addition to seeing a doctor, not a substitute.

Why daily beats weekly, even though the study says either works

The research says the split doesn’t matter. Real life has an opinion anyway.

“Two hours sometime this week” is a plan that depends on the weekend going well. It rains, someone has a birthday, and now it’s Sunday night and you’re at zero. “Seventeen minutes after lunch” happens or doesn’t happen today. You know by 1:30 whether you did it.

Small and daily is also easier to remember, easier to protect, and easier to restart after a miss. For more on the evidence behind time outside in general, see our guide to the science of touching grass.

That’s how GTFO is set up. It sends a daily nudge to get you out the door, and shows your hours outside this month and your days outside this year, so you can see how the small ones add up. If those minutes have to come from somewhere, the screen time guide shows how to swap them in for scrolling.

A week that gets you to 120

If you want a plan to copy, here’s one that fits around a normal job.

• Monday to Friday: 15 minutes outside at lunch. Leave the building, find the nearest green thing, walk around it. That’s 75 minutes.
• Saturday or Sunday: one 45-minute outing. A park loop, a trail, a long way round to get coffee. That’s 120.

Do that for a month and you’ve spent more than 8 hours outside.

Once 120 a week feels automatic, you can decide whether to go bigger. Some people aim for a thousand hours a year, which is a very different commitment. We did that math in the 1000 Hours Outside challenge for adults who have jobs.

For now: 17 minutes. Morning’s not going to walk itself.