Running Outside vs. Running on a Treadmill: Which One Is Better for You?

A treadmill can be your best friend for training in icy conditions or getting in early morning runs when dark conditions make outdoor running dangerous. 

Treadmills are great for pre-programmed speed workouts to keep you from constantly checking your watch and stressing about pace.

They can even be the difference between skipping a workout and knocking out a few miles close to home. 

Yet, there’s this pervasive school of thought that puts treadmill training below running overground, assuming you can’t successfully train on a treadmill or that it’s not worth running if you’re not outside. 

Some just find it boring.  

While addressing boredom is more of a personal endeavor, what this article can do is set the record straight on the differences in the two training methods, how to level the playing field, and when one is appropriate over the other.

How Is Running on a Treadmill Different from Overground Running?

There’s no way to answer this question succinctly. In some ways, treadmill running and overground running are equivalent, but not all. Examining the differences requires a more nuanced answer across several facets of research. 

Biomechanic Differences

Mechanically speaking, a runner’s form will not differ between running outdoors and running on a treadmill. It may feel different initially, but regardless of where you’re running, it takes an estimated 4-6 minutes of running to “settle in” to your natural gait. After that initial period, your treadmill form will be nearly identical to your overground gait. 

In one small study, it was noted that runners may increase their stride length and decrease their cadence slightly on a treadmill. The study did note, however, that running form was maintained throughout the run and all other biomechanic factors remained constant between overground and treadmill running. Additionally, it’s not uncommon to react to outdoor terrain with variations in stride length and cadence.

Overground Running

Metabolic Differences

Running outside creates a greater metabolic ask than running on a treadmill does. When you’re running outside, you have to physically “grab” the ground with your foot to pull yourself forward, whereas the treadmill feeds you the belt as you’re moving. 

Training indoors also cuts out wind resistance. While this primarily affects runners at faster paces, there is a difference in effort when you’re moving through the air, rather than staying in one place relative in space.

As you run outside, you also naturally react to the stimuli around you. You’ll have to deal with curves and corners. You might shorten or lengthen your stride slightly depending on the terrain, or move side-to-side to accommodate uneven ground or unexpected obstacles. You also vary your speed slightly, even if your pace remains consistent overall. These small changes, do play a minor role in the metabolic ask of overground running.

Differences in the Rate of Perceived Exertion

When you run on a treadmill, do feel like you work harder, or does it feel easier? 

For a significant number of runners, the treadmill can feel like it requires more effort to complete the same distance as overground running. This may be due to boredom — running outside offers a whole host of stimuli that running on a treadmill can’t compete with. On the other hand, some runners feel that treadmill is easier, citing the aid of the belt or the ability to just zone out, watch TV, and crank out miles.  

Scientific studies on the concept are limited, but offer some insight. In one such study,  athletes were asked to run outside at their preferred pace and then come inside and run on a treadmill. They were tasked with setting the treadmill to the same speed they were running outside, but couldn’t see any of the display. For the most part, the runners set the treadmill to a slower speed than they did overground, suggesting that the perceived effort of treadmill running is higher than overground, despite the opposite being metabolically true.

Is Training on a Treadmill Productive?

If we take these studies together, then running on a treadmill requires less energy but feels like more. So, the next logical question is, can you train on a treadmill? And better yet, is training on a treadmill productive? Will it do any good?

The short answer is yes, you can. Plenty of runners have seen have seen tremendous success training primarily on a treadmill. That’s not to say it can’t be done. Alaskan runner Chris Clark won the Women’s Olympic Marathon Trials in 2000 after training almost exclusively on a treadmill — and she did it with a 7 minute PR. She’s not the only one, either. 

There are, however, a few factors to consider when undertaking training on a treadmill.

Treadmill Adaptations 

If you plan on making treadmills a part of your training plan, or if that’s all that’s available to you, never fear. There are a few adaptations you can make to get the most out of your time. 

Start by increasing the incline to 1%. You’ll hardly notice the difference at first, but you might as the miles rack up. Studies suggest that increasing the grade of the belt (even minimally) asks enough extra of your muscles and metabolism to mimic outdoor running and compensate for the lack of air resistance. It’s not a perfect one-to-one, but it’s certainly a step closer. You could also just use a really big fan, but I can’t guarantee that’s scientifically backed.  

Be mentally ready for the ask — endurance suffered on treadmills, as well as the rate of perceived exertion. There is no metabolic cause for this, leaving the assumption that physical shortcomings can be attributed to the mental endurance aspect of treadmill running. Whether that means catching up on podcasts, watching Netflix, or practicing your race mantras, have a plan for when boredom sets in and the mileage isn’t accumulating as fast as you’d like.

Types of Treadmills

If we’re going to discuss the ins-and-outs of treadmill running, it bears mentioning that different types of treadmills offer different workouts. 

Up to now, we’ve been outlining information in terms of a standard, run-of-the-mill, rows-of-them-in-a-local-gym treadmill. You can control speed, incline, and probably have a handful of preprogrammed workouts to choose from, but you can’t run downhill and the belt is motorized over a flat platform. 

Curved Treadmill

Curved, non-motorized treadmills create a different set of demands for your body and mimic outdoor running a little more closely. The most well-known variety is the Woodway treadmill. While they’re certainly not common, there’s plenty of information online, and some local running centers may have them available. 

Essentially, the belt is set on ball-bearings, and each of the runner’s strides pushes the belt backwards, creating the moving track. Because the belt isn’t moving at a pre-set speed, the runner can react to stimuli more naturally, self-regulating their pace and increasing or decreasing effort without making a conscious decision to push a button and ease up. It also requires more metabolic effort — as with overground running, they have to pull themselves over the ground (or in this case, pull the ground under them).

When Is Treadmill Training a Good Choice?

Training on a treadmill can be beneficial in several cases:

There is certainly a time and a place for training on a treadmill, but before you put yourself in one camp or another, consider the pros and cons of both training methods. Most training plans will be stronger with a mix of overground and treadmill running.

What Are the Benefits of Overground Running? The Drawbacks?

For most runners, the call of the outdoors is enough to make venturing outside for a run worth it. However, not everyone has a beautiful or safe place to run, or might be limited by other elements. There’s a time and a place for overground running, and certainly some perks that go along with it. 


If you’re training for any sort of race, with few exceptions, getting used to running outside is going to mimic your race-day experience more closely. For first-time racers, knowing how road running feels before the big day is a plus — the experience is going to be nerve-wracking enough without introducing a whole new element. 

Depending on whether you’re racing a destination race or staying close to home, you might even be able to run part of the course prior to race day, or at least mimic the terrain. This can be particularly valuable for trail runners or races with particularly challenging courses (think a unique set of hills or technical elements). 

Whether you’re running on roads, trails, or sand, getting training time on a surface similar to your race terrain is going to prove valuable. If you’re not training for a race, mixing up your running surfaces can train stability in your lower legs and help to keep training interesting. 

In terms of metabolic benefit, as we discussed earlier in the article, running outside and overground will ask more of your body, increasing the metabolic and caloric benefit. For runners pursuing weight loss goals, this may be an important consideration.


Weather can have a huge impact on the feasibility of overground running. If it’s too hot or too cold, running outside can be damaging to the body. Running at temperatures below 0 fahrenheit is ill-advised, and running at temperatures under 30 may decrease your performance. Make sure to dress for the weather; gloves and headbands or hats will protect your hands and ears. Or, just hop on the treadmill and enjoy the comfort of climate control. 

Depending on the area you live in, running outside may also create a safety risk, particularly in the winter months when daylight hours are shorter.  You should always be aware of your surroundings when running outside — avoid using noise cancelling headphones and make sure someone knows when you’re going on a run and when to expect you home. 

For winter months, if you’re running before or after daylight hours, make sure you’re visible to others on the road or trail. Running with reflective gear or a headlamp is encouraged. Avoid routes with heavy traffic, no sidewalk, or blind corners.

What Are the Benefits of Running on a Treadmill? The Drawbacks?

I’m not going to address the entertainment factor here — some people like the treadmill because they can plug in and just zone, clocking miles and catching up on Netflix at the same time. For the other camp, nothing, NOTHING, is more mind numbing than logging runs on a belt, seeing none of the world, and missing out on the vitamin D fix. Let’s look beyond that. 


Treadmills offer an increased measure of control in your training in terms of climate, location, and pacing. You don’t have to worry about braving the elements, wearing exactly the right combination of outerwear, or whether the battery in your headlamp will last. You just get to run, presumably in a climate controlled, indoor environment. 

Treadmills also allow you predictable control around your pacing. You know exactly what speed you’re running and that it’ll stay the same, until you decide otherwise. This can be great for getting your body used to a set pace without having to check your watch constantly. Similarly, treadmills are great for interval training. 

Some treadmills even allow you to download or preprogram (on a USB) a specific race course, meaning that you can run a simulated version of all the uphills, downhills, and flat distance for your upcoming race. This can be especially handy if you’re living in a super flat area and training for a hilly course. It may not be exactly the same, but it’s better than the shock of hills on race day. 

As an added bonus, you don’t have to worry about stashing water or fuel along your run, planning your route with bathroom breaks, or figuring out how to carry everything you need. 


At the risk of beating a dead horse, you’re not going to get the same metabolic benefits training on a treadmill that you would running overground. It’s just going to be different. 

There’s also limited opportunity to train downhill running. Most treadmills can’t simulate significant downhill grades, and chances are, if you’re training for a hilly course, you’re going to have to go down as well as up (summits excepted, of course). 

You also run the risk of becoming dependent on the treadmill for pacing. While the speed settings can be a fantastic tool for getting used to a new cadence or running intervals, if you rely solely on the treadmill for dictating pace, you may be in trouble on race day. Running outside is vital to understand how to maintain pace or push yourself. 

Science Aside, It’s Up to You

At the end of the day, the answer to whether you should train on a treadmill or outdoors is: it depends. On a lot of things. 

This article covered a lot of factors, from weather to metabolic benefits to accessibility. Everyone has a unique set of circumstances built from a plethora of factors. Based on your particular circumstances, it may be necessary to train on a treadmill 6 months out of the year, or it may be that you only have to duck inside once or twice a month. 

Use your own insight to develop a plan that works best for you, and don’t be afraid to try different things. You’re not going to undercut all your cardio gains by trying a treadmill workout, and if you’re one of the runners who prefers indoor running, don’t be shamed out of it. It still works — you’re evidence. 

Treadmill Running

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