Running is an age-old beloved cardio exercise known for scorching calories, releasing endorphins and sculpting the legs. But if you’re looking to incorporate this dynamic activity as part of your fitness regimen, you’ve probably asked yourself, “Which is better — doint it outside or on a treadmill?”

Ultimately, there is no right or wrong answer as your style of running depends on your unique goals and preferences. However, there are certainly pros and cons to both.

Running on a Treadmill

More than 50 million Americans use a treadmill each year, making it one of the most popular pieces of cardio equipment. Whether at home or in the gym, treadmill advantages are many:

• Stop moving anytime you want, without adding extra time to get home
• Run safely on your own at any hour of the day
• Adjust speed and incline to meet your desired settings
• Don’t worry about weather or temperature limitations
• Protect your joints by running on a smoother, cushioned surface

Despite its flexibility, however, there are disadvantages to treadmill exercise too. Safety may be a concern if you’re prone to falls, sprains or balance issues, as you’re moving on a “conveyor” belt you have to keep up with. Similarly, terrain options are limited. You cannot turn on a treadmill or run downward, so you miss the opportunity to work a few key muscles.

Running Outside

Most serious runners and athletes will spend the majority of their time spent running outdoors — whether it’s on grass, pavement, tracks or even sand. Benefits to outside run workouts include:

• Enjoy fresh air, nature and variations in scenery
• Skip the expenses of home equipment or gym memberships
• Benefit from changes to terrain that target various leg muscles
• Enjoy the flexibility of running wherever you go

However, much like treadmills, running outside has its drawbacks. Safety is a concern at darker hours of the day and in locations without much human activity. Similarly, you are often constrained by weather (rain, snow) and temperature conditions (too hot, too cold). Another primary concern about outdoor run workouts is injury to knees, lower legs, feet and ankles.

The Bottom Line:

Both outdoor and treadmill running can help you meet and exceed your cardiovascular goals. If you’re not sure which is more beneficial, consider your schedule, physical condition and training motivations. If your focus is just on burning calories and improving your heart health, a treadmill will work fine. If you want to train key muscles and joints, running outside gives you more of an advantage. Ultimately, identify your individual preferences and decide from there!