Is it healthier to walk outside or on a treadmill? Experts reveal which has more benefits

Walking is a wonderful way to stay active and comes with all kinds of health benefits, including less back pain and improved fitness and mental health.

But what if the weather is unbearably hot or cold? Or what if you don't have easy access to a walkable area? Is walking indoors just as good for you?

While there are many unique health boosts that come from being outside, indoor walking or walking on a treadmill, can still be great exercise, says Stephanie Mansour, certified personal trainer and Start TODAY contributor.

Benefits of walking outside

Walking or running outside tends to be more challenging than inside, which may be a pro or con depending on your goals and your fitness level.

When you're walking outside, "there's more variation in your speed and your pace," Dr. Jeanne Doperak, a primary care sports medicine physician at the University of Pittsburgh Medical Center, told TODAY.com previously.

You'll also be more likely to encounter different inclines and types of terrain, Mansour adds, like uneven pavement or a rocky, dirt road. "Physically, the different surfaces challenge your balance more than they would if you were on a treadmill or walking in place inside," Mansour explains.

That means your workout will engage your leg muscles in a more "randomized" way, Mansour says. "When you walk uphill, you're using more of your glutes and hamstrings as opposed to walking downhill, when you're using more of your quads," she explains.

While you can replicate some of that by adjusting the incline on a treadmill, it's not the same as being challenged by what nature throws at you.

Simply being outdoors also comes with a ton of other sensory and mental health benefits, especially if you tend to stare at a screen while working out inside.

"There are a lot of physical benefits to being in nature, and (that's) been shown in many studies," Dr. Stacy Beller Stryer said on the TODAY show previously. These include reduced hypertension and risk of stroke, lower heart rate and risk of heart disease, improvement in diabetes symptoms and an increase in cancer-fighting cells in the immune system.

"It's important for people of all ages to spend time outside regularly," she said. Other research has shown benefits of being outside for our mental health, too, Stryer said, including reduced symptoms of anxiety and depression, as well as lower stress levels as measured by cortisol in the body.

“It’s always still good to go outside,” N’Namdi Nelson, an exercise physiologist at NYU Langone’s Sports Performance Center, told TODAY.com previously. “You want to look at different buildings, trees, birds, everything," Nelson said. "That’s going to be healthier for you than just looking at a screen all day.”

Mansour calls it the "meditative aspect" of being outside. She regularly encourages people to focus on the smell of flowers or a freshly mowed lawn, as well as the feel of the heat from the sun or a cool breeze on their skin.

"It helps you to be a little bit more present and in-tune with your body, as opposed to being on a treadmill or being indoors," she says.

Benefits of walking on a treadmill

Walking or running outside gives you natural variation in pace, incline and terrain, but using a treadmill takes that variability and unpredictability out of the equation. For some folks, that's a major benefit of an indoor workout.

"If you're someone who struggles with balance or is prone to spraining your ankle," Mansour recommends starting with indoor walking workouts, ideally on a carpeted surface. That will be lower-impact than walking on pavement outside or on a treadmill, she says. And if you prefer to walk on a treadmill, take advantage of the handrails, Mansour says, which will help keep you steady while you walk.

The other advantage, of course, is that your treadmill is still available rain or shine, which means getting your walk or run in during the day is convenient no matter what the weather is like.

Walking pads, which are small enough to fit under a standing desk, are a popular option to get steps in during the day. However, note that many walking pads don’t come with handrails. “If you’re someone that has any problems with balance or any problems multitasking, don’t even look into a walking pad,” Mansour says.  

Should you walk outside or on a treadmill?

If you can, the experts recommend trying to do your walking or running outdoors for the most well-rounded and mental health-boosting workout. But if you can't be outside for whatever reason, that's OK. Know that you're still getting major health benefits from your physical activity — indoors or outdoors, Mansour says.

She recommends people think about going for their walk like they're choosing an adventure for the day: If you enjoy going on your walk every day outside no matter what the weather is like, then stick with that routine, she says. If it helps, think of your sweaty summer walk "like a detox," Mansour says. "Or if you're walking in the winter and you're bundled up, look at it as free cryotherapy."

But if you're someone who's less motivated to get your walk in or someone for whom the weather is a major barrier, keep your treadmill in your back pocket as a perfectly fine alternative.

The most important thing is to get moving — and keep moving, Doperak said. "All in all, any exercise is good exercise," she added. "And the health benefits of exercise are just endless."

This article first appeared on TODAY.com. More from TODAY:

• Are olives healthy? Be mindful of this 1 thing, dietitians say
• Everything Lizzo has said about the wellness routines she's developed throughout her weight loss journey
• Kathy Bates opens up about 100-pound weight loss and addresses Ozempic rumors