The 13% Trick: How walking in nature lowers your effort

A runner on a forest trail with sunlight filtering through tall trees

Your legs feel heavy, your breathing gets ragged and the same loop that felt fine last Tuesday now feels like a hill climb. Most runners blame fitness, weather or sleep, they just blame workouts. The real culprit might be where you spent the twenty minutes before you started moving, maybe in nature?

A 2024 study from the University of Michigan and the University of Kansas found that people who walked through a quiet, natural park rated their physical effort roughly 13% lower than people who walked through a busy city street, even though the distance and pace were identical (University of Michigan). The same body, doing the same work, felt easier. That single number reshapes how you think about training recovery, pre-workout prep and the kind of runs you do on a hard day.

What the Researchers Actually Measured

The study used two groups. One group strolled through an arboretum, the other through a dense urban area. After the walk, both groups performed a treadmill test at the same speed and incline. Heart rate, blood pressure and oxygen use were tracked, but the most striking result came from the perceived exertion scale, the Borg RPE, where participants rated how hard the workout felt from 6 to 20 (University of Michigan).

The nature group consistently reported lower RPE values, even though their physiological markers were nearly identical to the urban group. Translation: their bodies were doing the same work, but their brains registered it as easier. That gap between objective load and subjective effort is the thing most runners never learn to control and the study suggests nature is one of the cleanest levers we have.

Why Nature Quiets Your Internal Noise

The leading explanation comes from Attention Restoration Theory, a framework developed by University of Michigan researchers Rachel and Stephen Kaplan in the 1990s. Urban environments force your brain into a state of directed attention. You process traffic, signs, other people, sirens and constant visual motion. That mental load pulls from the same cognitive reserves your brain uses to interpret fatigue signals from your body (University of Michigan).

Natural settings, especially ones with soft, repetitive features like rustling leaves or running water, give the brain a chance to switch into soft fascination. Your mind is engaged, but it is not straining. Once that cognitive tax drops, the perceived effort of physical work follows it down. You are not suddenly fitter. You are simply hearing your body more clearly, without the static.

A second mechanism involves the parasympathetic nervous system. Time in green space has been shown to lower cortisol, reduce sympathetic arousal and drop resting blood pressure by 2 to 5 mmHg in as little as 20 minutes (University of Kansas). When your nervous system is in a quieter state, the same pace feels less threatening and your breathing settles into a rhythm your body can sustain. That easy, conversational pace falls squarely into what exercise scientists call Zone 2 — and the zone 2 cardio benefits include improved mitochondrial function, better fat oxidation and a lower resting heart rate over weeks of consistent effort.

The Numbers Runners Should Care About

Thirteen percent sounds abstract until you translate it into workout terms. If your usual easy run clocks in at a perceived effort of 12, a nature-prepped version of the same run might feel like a 10.4. That is the difference between a workout that nudges you toward burnout and one that builds durable aerobic capacity.

• A tempo run at RPE 15 could drop to RPE 13 with a pre-workout nature walk
• Long runs feel 10 to 15% less draining, according to the study's effect size
• Recovery walks in green space reduce next-day soreness more than indoor walking at the same pace
• Perceived exertion is the variable most strongly linked to dropout in beginner runners and the easiest to lower

That last point matters. Most new runners quit not because their hearts fail but because every run feels like punishment. If a 20-minute park walk before a workout can shift that feeling, the habit payoff is enormous.

Where to Build This Into Your Training Week

You do not need a daily forest retreat. You need to be intentional about three windows: pre-workout, mid-week recovery and long-run pacing.

Before a hard workout, walk through a tree-lined street or a quiet park for 15 to 20 minutes. Skip the podcast. Let your visual system settle. You will feel the difference in the first kilometer of your run, especially if that run includes hills or intervals.

On recovery days, choose a nature path over a treadmill when possible. The study suggests the cognitive and nervous system benefits compound over a training week and they are not cancelled out by walking alone. Easy movement in a green setting recovers the legs and the head at the same time.

During long runs, when fatigue starts whispering that you should stop, try shifting your route to a tree-lined path, a riverside trail or a park loop. The change in environment interrupts the negative feedback loop between effort and emotion. Many runners report finishing 20 to 30 minutes longer than planned when they switch mid-run to a softer setting.

What If You Live in a Concrete Jungle

Not everyone has an arboretum nearby. The same research team found that even brief exposure to nature images and sounds can move the needle, though not as much as the real thing (University of Kansas).

• Watch a 5-minute nature video before your warm-up
• Train near a window with a view of trees, water or sky
• Use noise-cancelling headphones and play forest or rain sounds during indoor treadmill work
• Plan one longer outdoor workout per week, even if it means driving 20 minutes to a trailhead
• Walk the long way home from work through any green corridor you can find

The effect scales with the authenticity of the nature exposure, but it does not require a remote cabin. A pocket park, a tree-lined sidewalk or a 10-minute park bench workout can each move perceived effort down by a few percentage points.

How This Connects to Move-to-Earn Training

If you train with a move-to-earn app like Actifit, every step, walk and workout you log is already being counted. Adding a nature-based walk before a workout does not change how much you earn, but it changes the quality of the workout that follows. While most people search for walking for weight loss, the nervous system and performance benefits of a green-space walk may actually deliver faster results than the scale suggests — and you earn AFIT for both. You get more training value out of the same physical output and the habit compounds across weeks.

A 13% reduction in perceived effort is not a small thing. It is the difference between a runner who looks forward to tomorrow and one who dreads it. It is the difference between a consistent training log and one that slowly thins out. And unlike gear, supplements or fancy shoes, the lever is free, repeatable and available to anyone willing to walk out the front door.

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Use Actifit as your walking tracker to log every step, every walk and every workout — and earn AFIT for all of it.

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References

University of Michigan. Why a walk in the woods could make your next workout feel easier. Running Magazine. 2024.

University of Kansas. Why a walk in the woods could make your next workout feel easier. Running Magazine. 2024.

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