Running on a Treadmill vs. Running Outside

Running on a Treadmill vs. Running Outside

Lisa Jhung
Writer and Author of Running That Doesn't Suck: How To Love Running (Even If You Think You Hate It)
October 11, 2023

Running on a treadmill inside a gym or in your own home is a very different experience from running outside on a road or path of any sort. I’m a firm believer in beginning runners starting on the surface that makes them feel most comfortable, and which makes them look forward to running.

Those two bits of criteria don’t always match up. In this piece, I’m going to weigh the pros and cons of running inside on a treadmill vs. outside, and I’ll also offer some food for thought.

Running on a Treadmill: Pros ✅

runner on a treadmill

Running on a treadmill has the benefits of being a controlled environment. You don’t have to think about what route to run, getting hit by a car, or dealing with adverse weather. That controlled environment also applies to consistent terrain: you’re always running on that nicely padded surface of the treadmill belt, which is softer than most outdoor surfaces and absorbs impact on joints.

On a treadmill, you can also control your pace…and see what pace you’re running without having to wear and look-down at a watch. This can be great for training—both in making sure you’re running the pace you want to be running, and for learning what different paces feel like on your body.

You can also control your incline—how steep your running surface is—by simply hitting a button and increasing or decreasing the slope by 1% increments. (See below about setting a treadmill to 1% incline.)

And with a treadmill in a gym, or in your home, you can watch TV or movies, or listen to podcasts, audio books or music without having to worry about safety (having headphones in outdoors can create a safety hazard).  

If you’re coming back from injury, running or run/walking on a treadmill is a great way to ease back into things, as you can stop and get off the treadmill if something doesn’t feel right without being miles from home.

And on a treadmill that is in front of a mirror, or to the side of the mirror, you can gage your running form and see what adjustments feel like (i.e.: if you’re trying to run with a neutral pelvis if you’ve been told your pelvis tilts forward or back; or if you’re trying to run with arms that swing back and forth, not across your body).  

Running Outside on Roads, Paths, Trails: Pros ✅

runner outside on road

Unless you’re binge-watching a gripping season of a show you love while running on a treadmill, running outside is undoubtedly less boring than running indoors. Even running a plain, urban street gives you variety of scenery, while running in parks, or on scenic paths of any sort can give you a sense of exploration.

That variety of terrain is also good for your body. Hopping up and down curbs, making right and left turns, and negotiating everything from crosswalks to downed branches builds strength in your muscles and connective tissues. And while running either on a treadmill or outdoors builds bone health, conditioning your body to run on harder surfaces is arguably that much better for increasing durability.

Another physical benefit of varying terrain is the variety of paces that terrain demands. Changing up your pace varies your heart rate like a natural form of interval training, which is good for cardiovascular health and also makes you fitter faster.

Running outdoors also gives you fresh air and exposure to Vitamin D from the sun, plus the benefit of being among nature, which has been shown to combat anxiety and depression. (But if you only run on a treadmill due to health or other reasons, know that exercise in general has also been shown to help with anxiety and depression).

Running outside also allows you to run with a partner, a group, or a dog. Running on a treadmill is inherently individual, unless you’re involved in a treadmill running workout class.

Running on a Treadmill: Cons ❌

running on gym treadmills

Aside from not benefitting from the above list, there are a couple more “cons” for running on a treadmill.

Since the belt of a treadmill moves for you, you don’t have to engage the muscles and connective tissues that propel you forward as much as you would outside. That can lead to weaker glutes, hamstrings, etc. than if you were to run outside, and any weak body part can lead to injury.  

The repetitive motion of a treadmill—without the variety of terrain naturally created by the outdoors—can also exacerbate certain overuse injuries. You might find that your runner’s knee, for instance, feels better when running or hiking on a varied trail than it does running in a straight line on a treadmill or even down a flat, hard road.  

Running on a treadmill does cost money, whether you invest in one for your home or join a gym to use it, while running outside is free.

And running on a treadmill can get you too used to running on a treadmill, which means you may grow increasingly tentative about running outdoors or entering events, like a community 5K.

Running Outside: Cons ❌

woman running trail

With running outside, there is some thought involved: Where should I go? Will I be safe? What should I wear? That kind of thinking can be healthy, though. Learning to plan and strategize runs will only add to your arsenal of self-sufficiency both as an athlete and as a human.

Chances are, learning to dress for your runs in variable weather will cross over into other parts of your life, as will route decisions.

Weather can be a deterrent, but great gear exists for all sorts of weather. I don’t advise heading out in either an ice storm, a lightning storm, or when the Air Quality Index (AQI) is bad in your area. For those reasons, the treadmill can come in very handy, even for those who only ever want to run outside.

The Takeaway

With all that in mind, consider this: running on a treadmill and running outside both have their merits. And if you only do one, try the other sometime…especially if you’re lacking motivation or feeling burnt out. Change is always good in combating either and giving you fresh perspective.

If you do run on a treadmill, increasing the incline to 1% mimics the outdoors and so I encourage it. You don’t want to get so used to running on a treadmill at 0% incline that running outdoors feels incredibly hard.

And if you’ve only run on a treadmill and are intimidated by the outdoors, try heading to a local track, or a park that may have a looped path around it. You’ll likely feel comforted by the controlled environment, not having to decide what route to take, and the ability to stop if you need to or zone out while you run.

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