Running On The Treadmill Vs Outside: How They Differ

As a certified running coach, one of the most common questions new runners ask me is: “Is it better to go running outside or run on the treadmill?”

Like most aspects of running, there are pros and cons of outdoor running and pros and cons of treadmill running.

There isn’t necessarily a universal winner in terms of treadmill training vs. outdoor running, such as road or trail running.

Still, factors such as your fitness goals (and running goals specifically), the weather conditions, and the types of running workouts you are doing can impact whether it is better for any given runner on any given day to run outside or on the treadmill.

In this guide to treadmill vs outside running, we will discuss the shared physical and mental health benefits of running outdoors or doing treadmill workouts. We will then discuss the pros and cons of outdoor running and treadmill running to help you decide which type of running environment is best for you.

As a form of cardio physical activity, any type of running—indoors or outdoors—improves cardiovascular health and fitness, increases daily calorie burn, strengthens muscles, increases bone density, and improves physical and mental well-being.

What Are the Benefits of Treadmill Vs Outside Running?

#1: Controlled Environment

Treadmills offer a controlled environment with little to no wind resistance, temperature fluctuations, or uneven footing.

This makes running on the treadmill safer and more comfortable in inclement weather, such as when it is freezing cold or snowing, windy and rainy, or hot and humid outside.

The climate-controlled environment also allows you to stick with your running workouts and hit your target paces and heart rate zones without having bad weather conditions impact your performance.

Treadmill runners don’t have to worry about safety if they run alone or in the dark.

The best treadmills have excellent cushioning, which can decrease the risk of injury relative to road running on concrete or hard asphalt.

#2: Convenient

Running on the treadmill can be more convenient if you have a home treadmill and need to do your running workouts at home if you have children or can’t leave the house easily.

#3: Specificity

If you use a good treadmill with features like automatic incline and potentially even decline, you can do specific interval training workouts that simulate race conditions or do uphill running to work different muscle groups.

For example, to target the glutes, hamstrings, and calves, you can increase the incline and either do high-intensity interval training (HIIT) to simulate hill workouts outdoors or longer runs at a tempo pace for ultramarathon training (hello, long uphill climbs!) to increase lactate threshold with the added posterior chain muscle activation from the incline.

#4: Access To Entertainement

Some people find that watching their favorite TV show or movie while running increases motivation.

Some interactive treadmill running apps also have guided treadmill running workouts, which can sometimes serve as a substitute “running coach.”

#5: Can Run With People Of Different Levels

If you are running on the treadmill at the gym with a running buddy, you can each be doing treadmill running side by side and talking yet have very different running paces or treadmill workout scheduled, which can’t happen with outdoor running workouts.

This is a great option for partners of different fitness levels or following different training plans.

What Are the Downsides of Treadmill Running?

#1: Boring

Running on the treadmill can be monotonous and boring, particularly for long-distance workouts.

Even with motivating playlists featuring their favorite running songs or gripping true crime podcasts, many treadmill runners struggle to complete longer workouts that would otherwise be enjoyable while running outdoors.

#2: Does Not Exactly Replicate Running Outdoors

The treadmill belt is a moving belt, so the muscle activation is somewhat different and may not adequately replicate the biomechanics of outdoor running.

Because the motor pulls you along it is important to set the treadmill incline to 1%¹Jones, A. M., & Doust, J. H. (1996). A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences, 14(4), 321–327. https://doi.org/10.1080/02640419608727717 to replicate the metabolic and muscular requirements for road running outdoors.

Training exclusively on the treadmill instead of running outside may not prepare you for race day due to the terrain on the roads, the different muscle activation from having to self-propel as you run, and the challenges of wind resistance running outdoors.

Unless you are running on one of the best home or commercial treadmills, you likely won’t be able to simulate declines or downhill running.

This is key for marathon training for the Boston Marathon or other half marathons, marathons, and ultramarathons with lots of downhill miles.

However, some of the premium treadmills do have decline features. I absolutely love my BowFlex Treadmill 22. It allows you to run up to 12 miles an hour (5 min/mile) or adjust the incline and decline from -5% decline to 20% incline!

#3: Risk Of Injury

The repetitive nature of the smooth surface of the treadmill belt can increase the risk of injury from overuse unless you vary the speed and grade of the treadmill.

#4: Wears Out Your Shoes

The friction and heat of the treadmill’s moving belt can wear out your running shoes faster.

#5: Expensive

If you don’t have a good home treadmill, you need a gym membership for treadmill training, which increases the expense.

If you plan to do a lot of treadmill training, I highly suggest buying the COROS Pod 2.

This is one of the best running gadgets for treadmill training that I have seen.

Basically, it’s a little device that you lace into your running shoes that plots the motion of your foot through space.

This increases the accuracy of your treadmill pace running indoors and allows you to record your workouts and see detail

What Are the Benefits of Outdoor Running?

Aside from the normal physical and health benefits of running, running outdoors specifically provides additional benefits over treadmill running:

• Running outside better prepares you for race day because you can train in the actual environment and running surface for your race.
• The varied terrain helps use different muscle groups and decreases the risk of injury from overuse.
• Outdoor runners get fresh air and vitamin D from the sunshine, which can help improve mood and overall health and wellness.J², T. C., K, B., K, S., R, W., J, B., & Mh, D. (2011, March 1). Does Participating in Physical Activity in Outdoor Natural Environments Have a Greater Effect on Physical and Mental Wellbeing Than Physical Activity Indoors? A Systematic Review. Environmental Science & Technology. https://pubmed.ncbi.nlm.nih.gov/21291246/
• You don’t need a gym membership to run outside, which saves money.

What Are the Downsides of Running Outdoors?

As a running coach and competitive runner myself, I love road running and trail running over treadmill running, but I can still admit that there can be downsides to running outdoors, such as the following:

• You can’t control the weather conditions, so it can be slippery when running in inclement weather in the winter or super hot in the summer. I also hate running into a headwind!
• Trail running, in particular, is prone to uneven terrain, which can increase the risk of twisting an ankle. I also run in the dark on many roads with potholes, and this uneven terrain can cause me to trip.
• Running on cambered roads sloped from side to side can increase the risk of injury to the hips, knees, and ankles because one leg is always slightly higher than the other, putting the hips and pelvis in an uneven position.
• There is less cushioning on asphalt and cement relative to the cushioning of a treadmill belt and running deck, which increases joint impact stresses.³NILSSON, J., & THORSTENSSON, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica, 136(2), 217–227. https://doi.org/10.1111/j.1748-1716.1989.tb08655.x
• If you live in a flat area, it is difficult to do hill training and prepare for a hilly race. 
• You can’t multitask with outside running in terms of watching your kids or doing a treadmill workout next to a friend or spouse at the gym who might be using an elliptical machine or doing another type of exercise while conversing with you. 

As can be seen, there are pros and cons to running outside and on the treadmill.

Unfortunately, the treadmill is arguably one of the most simultaneously loved and hated pieces of exercise equipment at the gym. 

Indeed, if you’ve ever heard runners jokingly refer to the treadmill as the “dreadmill,” they are encapsulating the monotony and discontent they often feel by having to log a long run on the treadmill or do a treadmill interval workout rather than lace up their running shoes and hit the trails, roads, or track.

But, doing treadmill workouts occasionally can help you run faster in a controlled environment or avoid a winter storm!

For some treadmill workouts to get you started, check out this next guide:

The Best Treadmill Workouts For Runners

References

• 1
  Jones, A. M., & Doust, J. H. (1996). A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences, 14(4), 321–327. https://doi.org/10.1080/02640419608727717
• 2
  , T. C., K, B., K, S., R, W., J, B., & Mh, D. (2011, March 1). Does Participating in Physical Activity in Outdoor Natural Environments Have a Greater Effect on Physical and Mental Wellbeing Than Physical Activity Indoors? A Systematic Review. Environmental Science & Technology. https://pubmed.ncbi.nlm.nih.gov/21291246/
• 3
  NILSSON, J., & THORSTENSSON, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica, 136(2), 217–227. https://doi.org/10.1111/j.1748-1716.1989.tb08655.x