Running on Treadmill vs. Outside: Which Is Better, and Why?
Key takeaways:
Research suggests that the biomechanics of running on a treadmill and running outside are similar.
Both options have unique benefits and risks, so one is not inherently better than the other.
Whatever your running goal is, chances are you can achieve it by running outside or on a treadmill.
Ask runners if they prefer to run outside or on a treadmill, and you'll probably get compelling responses in favor of both. Some runners love the convenience of a treadmill. For others, nothing beats the fresh air during an outdoor run.
Find out what the research says about the pros and cons of running on a treadmill versus outside. Then, you can settle this debate for yourself — once and for all.
Treadmill vs. outside running: What’s the difference?
The most obvious difference between running on a treadmill and running outside is the indoor and outdoor environments. But you can enjoy the many benefits of running — from better heart health to less anxiety — both on a treadmill and outdoors. So your decision will depend on your preferences and fitness goals.
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Some research suggests that there are minor differences in the biomechanics of indoor and outdoor running. (Biomechanics refers to how your muscles, bones, and joints work together.) For example, one study found that runners strike the ground harder when running outside. But ultimately, evidence suggests that the biomechanics of treadmill and outdoor running are similar.
As for the physical demands, there’s some evidence that running outside can be harder than running on a treadmill. That's because factors like the weather and a rocky terrain may cause you to exert more energy.
What are the benefits of running on a treadmill?
There's a reason that treadmills are a staple of so many gyms. They offer important advantages for people who want a good cardio workout.
Treadmills are accessible and convenient
Treadmills allow you to run in a temperature-controlled indoor environment. That means you don't have to worry about bad weather affecting your run or stopping you from running altogether. And if you have one at home, you can safely run at any time of day.
Treadmills provide features to customize your runs
Treadmills provide predictability and control that isn't always attainable outdoors. You regulate the pace and the incline — two factors that determine the difficulty of your run. Incline training on a treadmill may improve your running economy, or how much energy your body needs to run at a certain pace. But there is no preset course with a treadmill, so it's all up to you.
Treadmills can be easier on the joints
Treadmill belts are designed to absorb shock, so they may be easier on your joints than tracks or roads. And because the surface is stable and unchanging on a treadmill, you can avoid unexpected obstacles — like bumps, potholes, or rocks — that may litter your path outdoors.
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Treadmills allow you to multitask
Want to watch TV or read while you run? You can do that on a treadmill, too. But you should be careful when multitasking. You don't want to compromise your form or put yourself at risk of falling.
What are the disadvantages of running on a treadmill?
There are, of course, downsides to running on a treadmill, too.
Running on a treadmill can't fully mimic outdoor running
You can recreate some outdoor conditions (like hills) with a treadmill. But it's a different experience. You won't get the same terrain, views, fresh air, or sunshine on a treadmill as you would outdoors. And you may not be fully prepared for an outdoor marathon if your training only includes treadmill running.
Running on a treadmill may get boring
Some runners might find the stationary and repetitive nature of the treadmill monotonous. But others find it therapeutic, so it depends on what you like.
Running on a treadmill may seem harder
There is some evidence that people feel like they're working harder when running on a treadmill. That may be because many people take shorter, quicker strides on a treadmill, which makes it feel like they're moving faster.
Running on a treadmill may cause injury
Like outdoor running, treadmill running can cause overuse injuries. It's also possible to fall off a treadmill or get pulled under the belt. This can result in head injuries and broken bones. Parents should also note that at-home treadmills pose a potential risk for small children.
Running on a treadmill can be expensive
Gym memberships, at-home treadmills, and indoor running classes all cost money. Those expenses add up and might be hard to maintain.
What are the benefits of running outside?
Many experienced runners will tell you that you can’t beat the benefits of running outside. Fresh air, variety, and cost effectiveness — it’s easy to see why some prefer the outdoors to a treadmill.
Running outside allows you to enjoy nature
Unlike treadmill running, running outside exposes you to fresh air, greenery, and sunshine. And many studies suggest that performing physical activity in nature is good for your mental health and well-being.
Running outside offers more variety
Outdoor running provides a change of scenery, less predictability, and the opportunity to run different routes. These factors can make running outside more interesting and help you avoid burnout.
Running outside might work different muscles
On a treadmill, the terrain is always the same. Outside, the terrain constantly changes. Hills, bumps, and different surfaces are just a few environmental factors you might encounter while running outside. Your body recruits different muscles to deal with these obstacles, which may present more of a physical challenge.
Running outside is free
Aside from the cost of running sneakers, clothes, and accessories, running outside is free. You can run for as long as you want, as many times as you want, at no charge.
What are the disadvantages of running outside?
Running outside is accessible and low cost, but the unpredictability means that there are risks. The potential for injury, inclement weather, and safety are important factors to consider when deciding between indoor and outdoor running.
Running outside in bad weather can be risky
Running in extreme heat or cold can put you at risk of temperature-related medical conditions like hypothermia and heat stroke.
Running outside may cause injury
Many running injuries are related to overuse, which all runners are at risk for. But varying conditions — like uneven terrain and other people on your path — can also cause falls during outdoor runs.
Running outside at night can be dangerous
Running outside at night raises safety concerns. For example, if you run on or near streets, drivers may not see you. And you may not feel safe running alone when it's dark outside. But there are various precautions — like wearing reflective clothing and headlamps or running with friends — that can be helpful.
Running on a treadmill vs. outside: How to decide
Your fitness level and goals can help you choose between running outside or on a treadmill.
For example, if you're training for a race, you'll want to prioritize outdoor running. Practice outdoors in conditions that are similar to those of your upcoming race. This will help you be prepared for those conditions and put your best foot forward on the big day.
If you're a beginner and want to boost your fitness, you might start by running on a treadmill. You can master the basics and easily track your progress, including how you’re doing on pace or distance. The treadmill is also your best bet if you have any safety concerns, such as encountering bad weather.
It might take some time to find out which option works best for you. But you also don't have to necessarily choose between one or the other. Adding treadmill and outdoor running to your fitness routine can help you work toward numerous fitness goals.
The bottom line
Whether you’re training for a race or running for heart health, there is room for both treadmill and outdoor running in your routine. One option isn’t necessarily healthier than the other. So it all comes down to what you find most enjoyable and accessible. You can accomplish any running-related goal you have — be it hitting a personal record or completing a specific distance — on a treadmill or outdoors.
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References
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Catapano, J. S., et al. (2018). Treadmill associated head injuries on the rise: An 18 year review of U.S. emergency room visits. Brain Injury.
Colino, E., et al. (2020). Mechanical properties of treadmill surfaces and their effects on endurance running. International Journal of Sports Physiology and Performance.
Ferley, D. D., et al. (2014). The effects of incline and level-grade high-intensity interval treadmill training on running economy and muscle power in well-trained distance runners. Journal of Strength and Conditioning Research.
Kaplan, Y., et al. (2014). Referent body weight values in over ground walking, over ground jogging, treadmill jogging, and elliptical exercise. Gait and Posture.
Kong, P. W., et al. (2012). Unmatched perception of speed when running overground and on a treadmill. Gait and Posture.
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