Some runners cringe at the thought of running on a treadmill. For others, having to tackle the elements on a regular basis makes it difficult to commit to a regular outdoor running schedule. While there is debate among runners over whether one type of running is better than another, it appears that there’s a place for both modes of running in any runner’s workout regimen.

Each type of running has its benefits and its drawbacks. There are good reasons to head to the gym to jump on a treadmill (or to do it at home), as well as reasons why you’ll definitely want to get outside.

Here are some of the pros and cons of treadmill and outdoor running:

Boredom. Running on a treadmill can be monotonous and seems to take forever. Just one mile on the treadmill can feel like 5 or even 10 miles outside. Changing scenery outside helps you pass the time, while the slowly ticking clock on a machine can make it feel like time is standing still.

Weather. The elements don’t affect you when you run on a treadmill, but they have an effect if you’re an outdoor runner. Not only can the weather stop you from getting outside to run, but heat, humidity, rain or ice can affect your workout even if you do get in your run.

Energy cost. The absence of weather-related elements when running indoors also means there’s no air resistance. The lack of wind resistance results in a lower energy cost at the same speed compared to running outside. But research shows that if you set the treadmill to a 1% grade, it simulates the same conditions as outdoor running.

Obstacles. When you’re running outdoors, whether on pavement, a track or a trail, you have to look at the ground in front of you to avoid anything that may cause you to trip or fall. On a treadmill, once you get going, there’s nothing to stand in your way. This allows you to zone out without having to worry about what you might step on.

Pacing. While treadmills make it easy to set a course and desired pace, you can lose your ability to find and maintain a pace. You’ll need to be able to do this if you’re training for races, so it’s good to mix up treadmill and outdoor runs.

Oxygen demand. The oxygen demand of running on level ground has been shown to be the same whether you’re running on a treadmill or outdoors, according to studies. This means you can get the same cardiovascular workout at the gym as you can if you head outside.

Muscle impact. When running outside, your hamstrings get more of a workout than when running on a treadmill. This is because the propulsion of the treadmill belt does much of the work that your hamstrings would do to finish your stride. Conversely, your quads get worked harder on a treadmill because you have to use them more to push off.

Balance. The treadmill provides a slightly unstable surface, thus requiring a little more balance than running on flat ground. However, you’ll often encounter unpredictable surfaces outdoors, which can challenge both your balance and your coordination.

Safety. There’s no worries about darkness, obstacles, weather conditions or being alone on a deserted path when running indoors. The treadmill also offers a more forgiving surface than pavement, reducing the impact on the body. This can be especially important if you’re coming back from an injury.