4 - Music and TV
If you're running outside all by yourself in a park it can get boring. You might have some good music but that's it. Inside you can watch your favorite TV shows. There's nothing that takes your mind off the run you're doing than an engrossing TV show you enjoy. You can look forward to setting it up all for your run.
5 - Softer surface and longer lasting shoes
While the treadmill is still high impact it's a softer surface than outside so your joints are protected to some extent. It's easier to run on as you bounce those miles away. You find your running shoes last longer if you do your runs on a treadmill. That's often one of the biggest expenses to running and you save money by exercising on a treadmill.
6 - You can run with people slower or quicker than you
Maybe you have an experienced runner as a friend you want to run with. On a treadmill he/she doesn't have to keep slowing down and waiting for you to catch up. You can run at your own pace and still have a conversation as you go. In a health club or gym with many treadmills you can have a whole group of you running at your own pace.
7 - You can use the incline
Maybe the way you exercise at the moment is power walking and there's no better place to do that than on a treadmill. Where it really excels is the incline. You can really work those glutes on your backside by climbing up an incline. With a treadmill you can specify how big the incline is and how long it lasts. No where in nature can you do that.
Those are just a few quick reasons why you should exercise on a treadmill. Ignore the people who say you should run outside, if you prefer the treadmill like we do then just do it. There is a kind of looking down on treadmill runners by those who run outside. We're trying to change the perception and with your help we can succeed. So keep enjoying your treadmill run like we do.