Most of us are aware, on some level, that we should spend more time outside. We’re also aware we should drink more water, call our mothers, and stop doomscrolling at 1 a.m. Awareness has never been the problem.

There’s now actual science for why ignoring that first item on the list is making things worse. Marc G. Berman, a psychology professor at the University of Chicago and author of Nature and the Mind, has spent his career in what he calls environmental neuroscience — the study of how your surroundings physically change your brain. His position, per a recent Men’s Health feature, is that nature deprivation is fueling the stress, chronic disease, and loneliness numbers we keep pretending are someone else’s problem.

The mechanism is attention. Berman draws on attention restoration theory, developed in 1992 by University of Michigan psychologists Stephen and Rachel Kaplan, which breaks attention into two types. Directed attention is what you’re burning through right now — at work, in traffic, on your phone. It fatigues. Involuntary attention is what engages when you’re walking through trees with nowhere to be. It doesn’t.

“A lot of these natural environments sit right at this nexus of being softly fascinating,” Berman said. Your brain gets a break without realizing it’s taking one.

Naturize Your Life to Lower Your Stress

The practical version of this is the 20-5-3 rule, developed by Pearson researcher Rachel Hopman-Droste. The framework calls for 20 minutes in green space three times a week, five hours in semi-wild environments once a month, and three days fully off-grid once a year. That’s the floor, not the ceiling — but it’s an actual number, which already puts it ahead of most wellness advice.

For city dwellers without reliable access to green space, Berman offers a workaround he calls “naturizing” — adding plants, nature photography, or organic design elements to indoor spaces. Brain imaging studies found higher resting-state neural connectivity in people viewing natural versus urban imagery, published in the journal Nature. Even fake plants can provide some benefit, which is either heartening or a small tragedy.

Manny Almonte, founder of Camping to Connect, a nonprofit running outdoor trips for young men of color, has seen the shift firsthand. “You give them permission to feel the grass,” he told Men’s Health, “and it’s like a revelation.”

Twenty minutes, three times a week. The bar has never been lower, but so many of us are still tripping over it.