Health.com published this article:

Physical activity is essential for bone, heart, and mental health-among many other benefits. It may be difficult for some people to figure out when to make the time for physical activity. But running on the treadmill is an easy and convenient solution to making time for physical activity.

For people who are pressed for time, don't have the budget for a gym membership, or live somewhere where the weather is cold and rainy often, it can be a beneficial way to get in your physical activity.

But working out on the treadmill can have benefits and downsides to it. Here's what you should know about using a treadmill versus running outdoors.

Running on a Treadmill
Is it better to run on a treadmill or outside on the pavement? It's an age-old question, and the truth is: There are pros and cons to both. 

There are some types of workouts you can do better or more efficiently on a treadmill. However, running on a treadmill can create that aimless, never-ending "hamster wheel" feeling for some. It depends on your goals, injury history, and preference, too.

Potential Pros
Treadmills provide an environment for you to exercise indoors. Here are three pros to running on a treadmill versus outside on the pavement or trail.

The Difficulty Level Is the Same
The difficulty level always arises when it comes to running indoors versus out. People assume that running outside is empirically harder than logging miles inside on a treadmill. 

However, you can adjust the incline and speed on the treadmill to make it easier, more challenging, or at the same level as running outside. You are in control and can decide what level you want to run at.

It's Easier on Your Joints
The smooth, cushioned belt is more forgiving than hard pavement or cement. Running on a treadmill can help reduce some of the impacts on the joints and the body. 

That can be especially helpful when rehabbing or coming back from an injury. Make sure you ease your way back to the road following an injury by alternating treadmill and outdoor runs-or try doing some exercises in the water-a few times a week instead of starting back immediately into road running.2

You Can Simulate Race Environments
Many more advanced treadmills allow you to create your unique course profile, which you can use to simulate your desired course. Even if you're not training for a race, you can switch up your workout by choosing a specific trail or terrain from around the world, depending on the options, to make you feel as though you're half a world away. 

You also have no worries about weather, temperature, or terrain issues while running on a treadmill, which can mean everything if you live in a very cold or wet part of the country.

Potential Cons
While there are benefits to running on the treadmill, there are a few downsides to it as well. Here are three cons of running on the treadmill versus running outside.

You Could Lose Your Agility
Although the treadmill might provide your joints with more cushion, you don't get the added benefit of running on uneven terrain or pavement. Even if the ground outside might feel flat to you, it never truly is. Therefore, your foot and leg muscles constantly make minor adjustments to adapt to the changing surfaces.

Those adjustments are significant for coordination and balance and will help improve your ability to do everyday things. While treadmill running can help improve your overall fitness, it will only mimic the real-life situations simulated running outdoors.

You Don't Work as Many Muscles
Because there is a machine powering the belt, the muscle mechanics differ when you run on the treadmill. Outside, you typically rely on your hamstrings to finish the stride cycle and lift your legs behind you, almost kicking your butt. But on a treadmill, the propulsion of the belt does much of that work for you.3

You use your quads to push off, but your hamstrings aren't firing as much as they would if you were running outdoors. If you're only running on the treadmill, be sure you're also doing cross-training to work the muscles on the back of your legs, including your hamstrings and glutes.

It's Boring
There are no two ways about it: Running inside is boring. Even if you have the best playlist or you're watching TV, it's just too easy to look at that clock directly in front of you and see that only 30 seconds have passed since the last time you checked it. (You can try covering the display with a towel to keep that clock out of sight).

When running outside, the time moves faster because you cover more ground. Plus, you set a literal finish line for your run and see it getting closer and closer as you approach it. That provides you with a more natural sense of distance and will give you that extra push to finish strong when you feel like giving up. Some evidence suggests that working outdoors can improve your mood, as well.4

Potential Risks
When using any exercise equipment, there is always the risk of injury. Maybe you lose your footing on the treadmill, or the incline causes strain on your ankles. 

It's essential to monitor your pace, be aware of your speed, and try not to push your body past its limit. As long as you focus on the exercise, you should be able to avoid injury.

A Quick Review
Running on a treadmill can provide some benefits but also some disadvantages. 

It is convenient to run regardless of the weather or terrain, and it's beneficial to control the incline and speed. But it may be boring, and you miss out on the agility and hamstring exercises that come with running outside.