Running is a sport with millions of passionate, knowledgeable enthusiasts.

One major question elicits many different opinions among runners: Which is better, running on a treadmill or running outside?

Proponents of both approaches share a love of running. However, some outdoor runners believe treadmill running is monotonous and boring, while treadmill runners may prefer running in a controlled environment.

Fortunately, you can reap benefits from either type of running.

This article reviews the pros and cons of treadmill and outdoor running to help you decide which is best for you.

A treadmill is an exercise machine with a controllable rotating belt that you can walk or run on. Treadmills are available in most workout facilities, or you can purchase one yourself in stores or online.

Pros

One of the biggest advantages of using a treadmill is its accessibility. Since most treadmills are indoors, you can use it day or night and in any climate. This can make running more accessible for those who exercise at night or live in places with ever-changing weather.

Most advocates of treadmill running enjoy the various functions a treadmill can offer, such as precise control of their pace, incline, and intervals.

This is also helpful for those returning from an injury, as they can progress slowly on a treadmill in a more controlled environment.

For example, running outside may pose a greater risk to someone returning from an ankle injury because of factors like uneven ground and slippery sidewalks.

Finally, running on a treadmill may be better for your joints since most treadmills have cushioned belts to absorb some of the impact. In contrast, hard ground, especially sidewalks and roads, will not.

Contrary to popular belief, most research shows that neither form of running causes knee or joint damage (1).

Cons

Unlike outdoor running, during which you can be surrounded by forests or beautiful greenery, indoor treadmill running involves staying in a fixed place where the treadmill is located. Some say this can become boring over time.

However, many modern treadmills provide screens to simulate an outdoor run, which may make the experience more enjoyable. Nonetheless, many argue this will never live up to running outdoors.

Additionally, treadmill running requires fewer muscle groups, such as the glutes and hamstrings, compared with outdoor running. That’s because when you run on a treadmill, you tend to run in a consistent linear motion with the treadmill belt propelling you forward (2).

A simple solution to this is to incorporate resistance training into your fitness routine a few times per week. This can help you work the muscle groups that treadmill training may miss.

Many runners report a less natural and shorter stride with treadmill running due to the limited parameters of the treadmill. However, this is controversial. A 2020 study found no significant differences in gait stride between treadmill and outdoor running (2).

Finally, one of the biggest downsides of treadmill running is the cost. Treadmills are available to use at the gym for $10 or more per month, while purchasing your own treadmill can range from hundreds to thousands of dollars.

Summary

Treadmill running is convenient, accessible, and lower impact than outdoor running. However, it tends to be more expensive and requires fewer muscle groups, and some people find that the unchanging environment can become boring.

Outdoor running involves running outdoors on a trail, path, sidewalk, or any other outdoor terrain.

Pros

Most runners find outdoor running far more enjoyable than treadmill running due to the changing scenery, fresh air, challenge of uneven ground, and unlimited options for running routes.

The increased variety can increase a person’s motivation to continue exercising (3).

Though both treadmill and outdoor running bring health benefits, such as lower blood pressure, greater endurance, and lower risk of depression, outdoor running may give additional benefits simply by helping you feel more connected to nature (3, 4, 5).

Interestingly, a 2016 study found that spending at least 30 minutes per week around outdoor greenery, such as parks and forests, could reduce rates of depression by 7% and high blood pressure by 9% (6).

Additionally, the various environments and barriers you may encounter while outdoor running can help you activate other muscle groups and develop better balance. Actions may include dodging other people on the trail, jumping over puddles, or running up hills.

Furthermore, research shows running outdoors can build stronger bones since you’re running on harder surfaces. This allows for greater gravitational force and stress on the bones, which is important for bone metabolism (7, 8).

Finally, outdoor running is completely free, if you exclude the cost of running shoes and workout gear. This makes running more accessible to people of all incomes.

Cons

It’s best to run outdoors in dry, moderately warm temperatures. Meanwhile, it’s less ideal and riskier in the rain, snow, and extremely cold or hot temperatures. Though with proper clothing, training, and preparation, you can run outdoors in most weather conditions.

Additionally, running in the extreme cold or heat can increase your risk of dehydration. This can be life threatening if you’re not wearing the proper clothing and rehydrating (9, 10).

Finally, running at night increases the risk of injury and can be dangerous.

If you choose to run at night, be sure to wear reflective clothing and a headlamp to help you see. Tell a friend your route and when you expect to arrive home. Better yet, find a running buddy.

Summary

Outdoor running increases your exposure to nature, which studies have shown may improve mental health and reduce the risk of chronic disease. However, running outdoors may not be possible for nighttime exercisers or those in extreme climates.

The best exercise for weight loss is exercise that you enjoy.

Whether you prefer treadmill or outdoor running, regular aerobic exercise like running will burn calories to achieve a calorie deficit (11).

One 2016 study found that running a few times per week led to increased fat loss. Interestingly, even though most participants experienced significant weight loss, they also gained muscle mass (12).

At least two different types of running may aid weight loss.

You can achieve weight loss with low to moderate intensity running, also called steady-state running. This means running at a continuous pace at the same intensity for a set period of time (13, 14).

Alternatively, you could use high intensity interval training (HIIT). HIIT involves short, 30–90-second intervals of intense exercise, such as sprinting, followed by an equivalent period of rest, such as slow running or walking (13, 14).

In a 2017 study, both HIIT and steady-state running helped people achieve fat loss. Weight loss depended on a person’s effort and enjoyment during the exercise, along with how often they exercised (15).

These results suggest it’s best to choose whatever type of running you can commit to.

Fortunately, you can do both HIIT and steady-state running on a treadmill or outdoors. However, if you’re sprinting outside, be sure to run on even ground to avoid injury.

Beyond weight loss, all forms of running can bring you numerous health benefits, such as reduced blood pressure, cholesterol, blood sugar, depression, and anxiety (15, 16, 17, 18).

If you’re new to running, be sure to speak with a healthcare provider first to make sure it’s right for you. It’s always best to start slow and gradually progress.

Summary

Both treadmill and outdoor running can help you lose weight at both high and lower intensities. Most research points to consistency and enjoyment as the key factors to long-term success.

Whether you enjoy treadmill or outdoor running, it’s important to run safely.

Before trying a new exercise routine, speak with your healthcare provider, especially if you have a chronic condition, such as heart disease.

Starting exercise routines too aggressively can lead to injury or more serious but rare outcomes, such as a heart attack (19).

Furthermore, make sure you’re consuming enough calories.

Studies have shown that extreme distance runners and those on severely low calorie diets have weaker bones, likely due to prolonged damage and lack of calories needed for proper bone repair (7, 20, 21).

Therefore, whether you run on a treadmill or outdoors, it’s essential to consume enough calories and allow yourself enough rest between runs for healthy recovery (20, 21).

Summary

Extreme distance running and not eating enough calories are the top causes of weakened bones and injury. Always speak with your healthcare provider before trying running for the first time or introducing a new training routine.

Running is best when you enjoy it and can do it long term.

Whether you prefer treadmill or outdoor running, you’ll experience many benefits, such as a lower risk of chronic disease and improved mental health.

Choosing which type of running best suits you depends on your budget, environment, and overall preferences. If you’re unsure, give both outdoor and treadmill running a try, or alternate between the two.

Either way, running is extremely beneficial for your health and well-being.

Summary

Running is very good for your health and well-being. You can reap excellent benefits from running on a treadmill or outdoors. The choice should come down to your personal needs and preferences.

Running on a treadmill and running outside each have their advantages and disadvantages.

Whether you choose to run outside or on a treadmill, it’ll benefit you both physically and mentally.

The best running for you is the type you enjoy and will stick to long term.