Have you ever met anyone who regretted taking a good, hard day hike? Me neither.

There’s something special about moderately paced movement through nature that leaves one feeling refreshed, renewed, and satisfied. Because of that, hiking is rarely considered a sport in the same way as trail running or mountain biking, both of which are more acutely painful and taxing on the body. And yet recent studies show that a walk in the woods—especially at the right tempo—is a superb way to build endurance and strength.

For a study published earlier this year in the journal PLOS One, a team of researchers affiliated with the University of Innsbruck in Austria had individuals complete two three-hour workouts under distinct conditions. The first was a “fast walk” on an indoor treadmill; the second was an outdoor hike through mountains. In the treadmill condition, the incline settings were contrived to mimic the outdoor route as closely as possible, so that the physical strain of both scenarios would be similar. (The researchers could not force the treadmills to decline, so outdoor downhill segments became indoor flat segments.)

During and immediately following both workouts, the researchers collected physiological and psychological measures. What they found is interesting, a bit paradoxical, and fully in support of hiking.

For starters, participants pushed themselves harder during the outdoor hike, as evidenced by heart rates that were, on average, six beats per minute higher. Given this, you’d think the participants would have experienced the outdoor hike as more tiring and perhaps less enjoyable. But the opposite occurred: They reported increased feelings of pleasure both during and immediately following the outdoor hike, and they said they felt less fatigued afterward. Put differently, going hard while hiking in nature feels easier than going hard indoors.

Of course, beating the enjoyment of a long workout on the treadmill isn’t such a high bar. But previous research published in Proceedings of the National Academy of Sciences examined the psychological effects of hiking in nature versus an outdoor walk in an urban environment. Those who went on a 90-minute walk in the wild not only self-reported decreased rumination but also demonstrated decreased neural activity in the part of the brain associated with anxiety and depression. In other words, hiking challenges the body and at the same time seems to soothe the mind.

Martin Niedermeier, PhD, lead author on the PLOS One study, says that nature—and green environments in particular—can reduce perceived stress and fatigue. “The visual stimuli in nature serve as so-called soft fascinations,” he says, “which might result in a lower perceived stress and fatigue.” Niedermeier says these findings are important for a simple reason: “People tend to stick with forms of physical activity they enjoy.”

Hiking is a great break from the monotony of urban running and road riding. In addition to being more enjoyable, hiking carries a reduced risk of injury while building fitness that is highly transferrable to most athletic pursuits. For these reasons, Jesse Kropelnicki, founder of triathlon training company QT2 Systems and coach to multiple Ironman champion athletes, loves prescribing day hikes as formal workouts.

“Many athletes get so caught up in their daily swim, bike, and run routines that they begin to operate with complete tunnel vision when it comes to incorporating other activities into their training,” says Kropelnicki. “There are a few unorthodox workouts that—even during the race season—hold merit, are efficient, and are actually quite specific. One such workout is hiking.”

In addition to the psychological reprieve, Kropelnicki says hiking offers a handful of unique benefits for the body. “The total time spent on your legs and eccentric loading [that is, lots of downhill] are great for strength,” he says, “and the extended duration of taking in nutrition while working relatively hard helps train your gut to efficiently digest and use calories while active.”

For some people—particularly the type A, metric-obsessed endurance athletes so common in mountain towns—the phrase “going for a hike” might induce bouts of hyperventilation. But Kropelnicki says turning your long run into a hike is as simple as multiplying its duration by 2.85. (For example: a two-hour run becomes a day hike.) The effort level should be hard enough to make you sweat, but at no point should you feel like you’re running, with the exception of extremely steep downhills.

As for when to swap out traditional workouts for hikes, Kropelnicki recommends doing so any time “at least six weeks out from sport-specific races.” This means that if you’re training for a competitive endurance event this fall, now could be the perfect time to take a hike. I can promise you won’t regret it.

Brad Stulberg (@Bstulberg) writes Outside’s Science of Performance column and is author of the new book Peak Performance: Elevate Your Game, Avoid Burnout, and Thrive with the New Science of Success.