Treadmill vs Outside Running: What’s the Difference?

Whether you’re new to running or a seasoned veteran, you’ve probably heard the debate between running outside vs. running on a treadmill. It’s been going on a long time.

Both options are pretty simple and accessible. Just about every gym has at least one treadmill, usually several, so you don’t even need to own one to use it.

The outdoors? Well, it’s all around us, literally. While you may have to drive to get to a location to run, generally speaking, you can run just about anywhere.

But the real question that everyone wants an answer to is whether one option is better than the other.

As a running coach who appreciates the versatility of the treadmill, I understand the allure of both choices. This article aims to explore the debate between treadmill running and running outside, helping you make an informed decision that aligns with your fitness goals, preferences and lifestyle.

And just to get this out of the way, around here we make NO JUDGEMENTS about where, when or how anyone runs. So do what works best for you to create consistency in your training.

Running on a Treadmill Vs Running Outside

We’re going to talk about the pros and cons of each, but I think first we just have to get some common questions out of the way.

No the treadmill is NOT doing the work for you.

No you are not more of a runner for going outside in all weather. We’re all runners, period.

Treadmill running can feel harder, this is common for a lot of folks. The goal is to focus on your overall effort for the workout and not be so focused on pace if one of those reasons is making it more difficult. On the flipside, other runners will find that they’re faster on the treadmill!

But what about your training?

Is it better to run on a treadmill or outside?

The consistent, cushioned surface of the treadmill provides a controlled environment that reduces the impact on your joints, making it an ideal choice for those who seek a lower-impact workout. It’s a form of running that can feel gentler on your body, particularly if you’re recovering from an injury or wish to minimize the risk of impact-related discomfort.

Meanwhile, the natural variability of terrain, from uneven trails to city streets, demands more from your body in terms of balance, proprioception, and adaptability.

The higher-impact levels of outdoor running can put more stress on your joints, but this also contributes to building greater bone density and overall resilience.

Is Running on The Treadmill As Effective As Running Outside?

Yes. You are still required to move yourself forward, to engage your muscles and to have the stamina and speed to complete the workout.

I even know many ultra runners who train through the winter on treadmills by utilizing the massive incline options. They’re still building all of the leg strength and power needed. Then as the weather improves, they go to the trails to work on those additional foot work and ankle strength skills needed.

Do You Lose More Weight on A Treadmill Or Running Outside?

In general, the calorie burn is going to be roughly the same. A mile at any pace is going to average about 100 calories.

The thing that can make the biggest difference is changing the treadmill incline. Now you’re going to increase the intensity and therefore increase the overall calorie burn. Running outside most of you won’t be doing 3 miles at a 10% incline so this is generally negligible.

You’ll burn the most calories from whichever one you can do most often and build to increase your total workout time.

So that’s our high level look at things and I hope what you see already is there are benefits to both training styles. What’s going to matter long term is what allows you to train consistently and be ready for race day.

Can You Train for a Marathon on a Treadmill?

100%, I know plenty of fast and strong athletes to who put in the majority of their miles on the treadmill. While some folks will tell you that doesn’t prepare you for running outside, I think that comes back to your overall training.

Are you utilizing the incline function to best mimic your race course?

Are you mentally prepared to run in a variety of weather conditions? Because that honestly is a big factor over the weather itself.

Is it ideal to ONLY train on the treadmill, no. But if it’s the only way that you can stick to the training, then get it done.

Ideally we want you to put in some miles outside so that you are able to adapt to running on concrete or pavement, which don’t have the same level of give as the treadmill. But you can mimic a LOT of variables from heat to hills on the treadmill.

Don’t take my word for it, here are some examples!

Jacky of NC Jacky
Recently ran 100 marathons, 1 a day and used the treadmill for many of them. She is an amputee who went from never running to doing ultras. And I’m gonna say she’s absolutely a real runner who uses the treadmill. Not because she can’t go outside, but because it made it feasible in the 100 degree AZ temps.

Oh and then there are those silly Olympians who use it, Emma Bates, Scott Faubs, Sara Hall and the list goes on.

Do You Need to Run at 1% On the Treadmill?

Nope. The data shows that only for those running faster than 8MPH are you truly going to create the “resistance” that would be similar to running outside by running at 1%.

However, you absolutely SHOULD be using the incline. Try to vary it throughout your run to utilize different muscles and change the intensity level.

If you’re doing a lot of treadmill running and only using 1% you may be overworking your hip flexor muscles.

Is it bad to run on a treadmill?

No. It’s not.

I get this question a lot and I can’t figure out why. Maybe because you think it’s easier? But a lot of runners would fully disagree and say they think the treadmill feels harder.

If it’s easiest for your mental health to use the treadmill, then get on it!

Why Use a Treadmill Instead of Running Outside?

There are a lot of reasons a treadmill may be your method of choice when it comes to running and training. Whether it’s because of weather, controllability, or being able to multitask, there are a lot of reasons using the treadmill may be a good choice.

If you’ve never understood why someone might make that choice, then read on so that you can better empathize with your fellow runners and drop the judgment.

Weather

Have you ever stalked the forecast to figure out when you’re going to get your run in? Maybe you’re trying to avoid a thunderstorm, get out there before it’s too hot, or you’re worried about ice and snow.

Personally, I’m just not going to mess with black ice which is a major factor on early morning runs here in Denver. And when I trained in Miami, I wasn’t interested in trying to run through 100 degree temps. So instead the treadmill offered up a solution to get in a quality workout.

Regardless of what the forecast may say, if you want a foolproof way to avoid weather issues, hit the treadmill.

GI Issues and Fuel Testing

One thing that many treadmill runners point out is the need to have a bathroom nearby. Whether this is because they have ongoing GI issues or are simply working on fueling this makes sense.

When you are testing out a new gel or learning how to increase your fueling on the run, there is the potential for a sudden bathroom need and that’s really inconvenient 5 miles from home.

Safety Concerns

The treadmill, be it at home or the gym, also offers safety. This is something I’ve heard increasing concerns over from female runners who aren’t sure about running alone. I’ve talked a lot about feeling confident to run solo, but you have to build up to that.

At certain times of year we only have so much daylight so that can leave us running in the dark if we head outside. That is totally fine, but can take more planning and may even mean a financial investment.

You need to find a safe route to run and you’ll want to look into reflective running gear (high visibility gear) and running lights to make sure you can see where you’re going and cars, cyclists, and other pedestrians can see you.

Maybe you don’t live in the safest area in regards to crime or maybe you don’t have easy access to roads with sidewalks or a bike path. Running at the gym or at home ensures you can stay safe regardless.

Convenience

Running at home or at the gym can be more convenient. Maybe you go to a gym that’s located on your way to and from work, and maybe it has security and a wide range of hours making it easier for you to get there at a time convenient to your schedule.

Or if you have a treadmill at home, you can get that run in whenever you have a bit of time to spare. For many parents this is a massive issue and one of the few ways they can ensure that runs are able to happen.

Control of Pace and Incline

Treadmills also offer the ability to customize your run in a very controllable way.

With speed and incline controls at your fingertips, you can ensure you’re getting the precise workout you need and want on any given day.

Whether it’s an easy, slower-paced run or you have speedwork on the calendar, a treadmill allows you the flexibility and customization you crave but may not be able to get outside.

Climate Control

When you’re looking at the forecast and see a crazy low windchill or maybe it’s the exact opposite and you’re seeing excessively high temperatures, no one will fault you for heading to the treadmill.

Regardless of what the weather is doing outside, your treadmill is in a climate controlled environment. You will still sweat most likely, but at least it won’t be brutally hot, cold, snowy, or rainy!

Multitask

While you do want to be careful on a treadmill, you can multitask in a way you may not be able to outside.

You can safely wear earbuds or headphones, watch TV, listen to podcasts, or even read a book. That last one is a bit more challenging, but some people definitely do it (I used to read magazines all the time).

I’ve even seen people take meetings on Zoom while on the treadmill. No one can smell you, so I guess why not.

Joint Health

One of the things you’ll notice equipment companies publicize are their cushioned treadmill belts. While injury likelihood isn’t significantly different among those who choose to run inside vs. outside, where those injuries occur and the stress on your body is different when using a treadmill.

As mentioned, the cushioned belt on a treadmill has been shown to be easier on your joints. Obviously, it has a lot more give than asphalt and concrete. It also may provide more energy return to help make running feel easier.

Are There Disadvantages to Using a Treadmill?

As you can see, there are a lot of pros to running on the treadmill. However, just like with anything else, there are some cons or disadvantages too.

No Downhill Running

Unless you have a treadmill like my Nordictrack 2450 that offer a negative incline option, you cannot run downhill on a treadmill. This has become a more common feature, but is rare in gym treadmills.

While that might not be a terrible thing if you’re just running to maintain your fitness, if you’re running in preparation for a race, being able to run downhill is important.

Running downhill engages muscles differently and can affect your gait. There are races that have a lot of downhill and that downhill can fatigue your muscles just as much as uphill running. You should make sure your body is prepared for that.

No Lateral Movement

When running on a treadmill, you’re pretty much stuck going forward. There’s really no other option that won’t involve a crash and burn.

Running outside offers you the ability to run on different terrain, make turns, and more. This is important for a number of reasons, including race preparation and injury prevention. Running outside will engage those important stabilizer muscles and forces you to adapt a bit more to the terrain.

May Impact Gait

Running on a treadmill may also cause changes in your gait compared to running outdoors. A 2019 study found that running exclusively on a treadmill may impact how your foot lands. As a result this can decrease load in some places while increasing it in others.

Like I’ve already mentioned, running one place or the other doesn’t make you more or less prone to injuries. But what may change is where an injury may occur.

The “Dreadmill” Talk

A common nickname for the treadmill is the “dreadmill.” This is because running on the treadmill can be dreadfully (see what I did there?) boring to some people. But as a running coach, I’m so over this!

If you call it the dreadmill, of course you’re going to hate doing it!! Stop making it harder than it should be with this talk.

Even if you have a TV, the best podcast, or awesome music, running on it can be very monotonous. This can be especially true if you’re tackling long distances training for a marathon where you could be there for hours.

What Are the Benefits of Running Outside?

As someone who enjoys the flexibility having a treadmill provides, if you follow me on social media you know I love running outdoors and regularly share the beautiful scenery. And that’s just one of the many benefits to running outside. Here are others!

Accessibility

Like I said early on in this article. Running is a pretty accessible sport and you can do it just about anywhere.

If you travel for work or pleasure, there’s often a hotel gym or maybe you have a nationwide membership to a chain. Even with those things, sometimes there isn’t a treadmill or you’re in a place where there’s not a gym. What are you to do?

Head outside! Running when traveling is a great way to see the sights and explore a new city or park. Do remember to take precautions in a new area for your safety. If there’s a local running store, see if they offer group runs or maybe your hotel has a concierge that can recommend safe routes.

Variety

Running outside provides a lot of variety. You can run on different surfaces like dirt, grass, gravel, asphalt, and concrete, for example.

All of these feel different and can affect our bodies differently. Uneven terrain, be it dealing with curbs or trail running in the woods, engages muscles we might not use as much and can impact our joints too.

There will also be terrain changes. Even if you live in a flat area, outdoor running offers variability you won’t easily mimic on a treadmill. I promise there are hills just about everywhere, even if they’re a bridge.

Improved Race Preparation

If you’re training for a race, it’s helpful to get in time outdoors on the surface you’ll be running. If you’re trail running, head to the trails. If you’re running a flat race, mix in some routes that are pretty flat. Racing on rails to trails? Try to find a similar surface to train on occasionally.

The more your body is used to what you’ll experience on race day, the better off you’ll be.

Nature and Fresh Air

In addition to the varied scenery, running outside gives you the chance to enjoy nature and breathe fresh air.

You’ll also get your daily dose of vitamin D, which is something many people don’t get enough of since we spend so much time indoors.

Spending time outside is also great for your mental health, can boost energy levels, and reduce feelings of anxiety, stress, tension, and depression.

Less Expensive

While many would argue that running outside is inexpensive, the reality is running can be expensive regardless of where you run. Shoes, clothing, watches, etc. all add up, although those are expenses you’ll have regardless of where you run most often.

However, if you plan to be an outdoor runner exclusively, you won’t need to buy a treadmill or invest in a gym membership. So, I guess you can say that’s a cost savings!

Where Should You Run? Outside or on the Treadmill

As you can see there are a lot of factors that will impact where you decide to run. The best advice I can give is to mix it up if at all possible.

If you have your own treadmill or a gym membership, on those bad weather days or in low light conditions, hit the treadmill. But when able, head outside, get some fresh air, and hit the pavement. Your body and mind will thank you for the variability both will provide.

Just remember that you need to do what’s right for you. This is a personal preference and a personal choice. What’s right for one person may not be right for the next. Choose the best option for you.

FAQs

Here are a few additional frequently asked questions that may help you when deciding where and how to run.

#1 Can you use an elliptical instead of a treadmill for indoor run training?

Another longstanding question is whether an elliptical is a good substitute for a treadmill or running outside.

Both machines offer many of the same benefits from a cardiovascular fitness perspective and for safety. But there are some key differences.

While treadmills may have more cushion than outdoor running, ellipticals remove all impact since you’re standing on pedals. Ellipticals also offer resistance to make a workout easier or more challenging. In addition, thanks to the moving handles, ellipticals can help engage the muscles of your upper body.

Ellipticals are common at most gyms and can be purchased for in-home use. They can be just as bulky as treadmills, although more compact versions are available.

Because they minimize impact, they can be great when dealing with or recovering from an injury while allowing you to still get a cardio workout done.

Like in the debate between outdoor running and treadmill running, when it comes to the elliptical vs. the treadmill, it’s best to mix it up.

#2 Is there a specific incline my treadmill should be on when running to better mimic outdoor terrain?

So the age old myth is that when running on the treadmill, you should set the incline to 1% to better mimic the outdoors, particularly wind resistance and the air you have to displace while running.

However, if one delved deeper into the study that determined this percentage, it was only accurate for people running faster than 7:09/mile.

Let’s be honest, most people don’t run that fast generally speaking so this really is a non-issue. Set the treadmill to whatever you want.

Actually, check out my Reel with what I suggest for most of us runners on the treadmill. Spoiler alert: mix up your incline throughout your run!

#3 Are some treadmills better than others?

Yes! If there’s a big purchase (outside of your home or car) that you don’t want to skimp on, it’s a treadmill. Good treadmills can last for a long time. I should know, mine has 18,000+ miles on it!

However, in an attempt to not skimp, you don’t need to break the bank either. I have several articles highlighting treadmills I’d recommend. If you’re looking for a budget friendly treadmill, check out my article highlighting the best treadmills for under $1,000.

If you want a treadmill geared more toward walking, check out my top 7 walking treadmills article. For running at home, check out these 8 treadmills. I also have articles comparing NordicTrack and Proform and Peloton vs. NordicTrack.

Hopefully among those articles, you’ll find the info you need to make a sound purchase. Obviously I’m a fan of finding a great at home treadmill.

#4 I’m a beginner runner. Should I stick with treadmill running or outdoor running?

When it comes to exercising, what’s most important is finding something you will stick with. It’s no different with running and new runners.

If you’re a new runner, figure out what’s going to get you to show up consistently. If having a treadmill in your basement makes it easier for you to lace up and run, then do it. If heading outside with a friend or for some time alone with varied terrain and things to look at will keep you motivated, then go that route.

There’s no one right answer. It’s whatever will get you to show up day in and day out for you.

Whew this was an exhaustive way to go through treadmill vs outdoor running to tell you that IT ALL COUNTS.

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