Is Walking on a Treadmill or Outside a Better Workout?

In one corner, you have a highly advanced computer, designed and streamlined to offer you an exclusive exercise experience. In the other, you have the great outdoors, brought to you by Mother Nature herself.

When it comes to choosing the best place for your walk, how do you decide who wins in the battle of treadmill versus trail, road or path?

The simple answer is there is no simple answer, says Galina Denzel, a restorative exercise specialist and personal trainer. Though she typically recommends walking outdoors when possible, there are a wide range of reasons why a treadmill workout might be better for a given person or a certain occasion.

Taking a walk is one of the most simple, inexpensive and non-intimidating forms of exercise. And there's no motion more natural than striding across the ground outside.

If you cover varied terrain — from hills to soft grass to hard concrete — you'll challenge your body in different ways, improving your strength and balance and reducing your risk of overuse injuries. These shifts in stimuli also keep your brain engaged and strengthen your proprioception, the mind-body connection that allows you to understand where you are in space.

With most of our work and personal lives focused indoors, fresh air and green space offer significant mental benefits, Denzel says — and research backs her up. In one study published in June 2015 in the journal Landscape and Urban Planning, a 50-minute nature walk decreased anxiety, lifted mood and also improved participants' performance on memory tests. In other research, published in July 2015 in the Proceedings of the National Academy of Sciences, it was shown that time in lush environs reduced people's tendency to brood or ruminate.

Read more: Outdoor HIIT Workouts for More Time in the Sunshine

Because we spend most of our days staring at screens, walking outdoors also gives our eyes a much-needed break. Focusing for a bit on what's far away and out to the side, rather than right in front of our noses, also calms our stress response, Denzel points out.

And if you walk around the area where you live and work, chances are you'll deepen your ties to the community. That wards off loneliness, which — according to a research review published in November 2017 in the journal Public Health — is linked to mental health conditions, cardiovascular problems and maybe even an early death.

Denzel especially appreciates this perk; she recently moved to Colorado, where she and her husband often encounter neighbors on regular strolls. "There are a bunch of 90-year-olds who walk — and it's so fun to see them out there walking and talking," she says.

Of course, walking outdoors won't work for everybody. Depending on where you live, weather conditions might prove less than hospitable during certain times of the year. If you're a single parent who can't leave a child alone, an older adult with vision or hearing problems or live in a part of town where you don't feel safe striding, you might not feel comfortable — especially on your own.

Especially if you fall into one of the previously mentioned categories, a treadmill at your home, gym or office building might be your best option to keep moving.

The future of fitness involves shorter, more high-intensity workouts, says Tom Holland, an exercise physiologist and author of Beat the Gym: Personal Trainer Secrets — Without the Personal Trainer Price Tag.

Having a treadmill in your home or other convenient location allows you to hop on at a moment's notice, log 10 minutes of harder pacing, then do it again later in the day. "Every minute counts," Holland says. Given how many people cite lack of time as a barrier to working out, treadmills make fitness that much more doable.

The digital display can prove highly motivating, Denzel says. "You can see how fast you're going and how far you went, and you can see your heart rate — things that you normally can't see outside," she explains. "And humans like to see what they've done."

Plus, technology has advanced so much that in some cases, it's tougher to distinguish between indoors and outdoors. "You can literally put on your treadmill and walk the streets of Rome virtually with other people," Denzel says. And you can do it without feeling self-conscious about your pace, your clothing or your body.

Another advantage? If you live where it's flat, the treadmill can provide inclines. Uphill walking is especially good for strengthening ankles and calves, Denzel says. (Not to mention your hamstrings and glutes too!) If you're preparing for a hike or trek in a hilly or mountainous area, you'll want to mimic that terrain in your regular workouts.

Read more: What Are the Health Benefits of Walking an Hour a Day on the Treadmill?

All that said, treadmills do have a few downsides. They don't always support your natural gait mechanics because the belt moves you along and doesn't push back with the same force as the ground does when you're walking on a more stable surface.

Problems with knee alignment, flat feet, pelvic floor disorders or low back pain are sometimes exacerbated by treadmills, because of the way the belt moves you forward, too, Denzel says. "And if you're prone to vertigo or you have any other vestibular system [or inner ear] issues, it might be challenging," she says.

Finally, treadmills do come at a cost — for a high-quality model, sometimes a steep one. "Crappy treadmills are, well, crappy," Denzel says, and likely create even more biomechanical challenges. (In the market? Try the ProForm 505 CST, which comes relatively moderately priced at $600, ascends to an incline of 10 percent and has a 2.5-horsepower motor to power it up to 10 miles per hour). Even a membership to a gym isn't always available or budget-friendly.

The bottom line, Holland says, is to do the type of exercise in the location that feels most fun and inspiring to you. That way, you're more likely to stick with it for the long haul.

For optimal mental and physical results, Holland suggests not putting limits or constraints on your physical activity by declaring yourself only an outdoor enthusiast or a gym rat. "I'm always a big proponent of mixing it up and doing both," he says.