My most evocative scent memories of running are tied to high school, a time when, as a member of a close-knit team deeply invested in winning, the sport could feel like life or death, every race a dogfight. The heightened awareness has vividly preserved my sense impressions of that age. The smells of running are often the smells of the places we’ve run. The brine of ocean and sand, the fresh, green aromas of cool summer nights and wet grass when the sprinklers click on. The gladiatorial fume of a polyurethane track baking on a hot day.

For Katie Arnold, an ultrarunner and author of the new memoir Running Home, her formative time as a young athlete living alone in Boulder, Colorado, will forever be tied to the butterscotch-like wafts from Ponderosa pines. “It smells like summer and heat and freedom and just being alive in the mountains, moving,” she says. Now, living in Santa Fe, New Mexico, and running on trails, the dominant smell Arnold experiences is of sagebrush. “It’s a powerful, very sweet smell that reminds me of all the times I’ve spent on Western rivers, and that you have to go with the current,” she says. Sometimes, Arnold will even stop to clip a sprig of sage and put it in her running vest.

Beyond scents imprinted by repetition—my IcyHot, Katie’s sage—some running smells stick because we link them to something we encountered for the first time: the coppery, metallic burn inside your nostrils when finishing your first truly brutal interval workout, a fragrant platter of huevos rancheros after setting a 10K PR.

Other smells are inextricably tied to ritual. Flashing back to my last marathon training, I get a whiff of the cucumber-​ mint energy gel I brought with me on long runs. It is the scent of relief: medicine, dosed out in tiny salves, for interminable treks.

Certain running scents are visceral, the kind that make you wrinkle your nose: sweaty socks, damp shoes, stale sweat that’s turned to salty crust on your skin, reminders that we’re still part animal.

This is something subtle that running does for us, beyond the toned legs and feel-good brain chemicals; running re- immerses us in the physical world, and in a way that our jobs, at least the white-collar ones, do not. Workplaces are scrubbed of appreciable sights and smells, leaving only the most anodyne impressions: hand soap, linoleum counters, beige walls, fluorescent screens. These aren’t the environments we were built to live in. Our senses were honed over centuries to navigate the world and survive by sensory data. When we run, we reawaken to the brightness and clarity of that drive.